You make a good point though that doing some sorts of science are much cheaper now than they used to be, in large part because of cheap computing, so you can simulate and communicate and archive cheaply in a way never before possible. So yes, "professional amateurs" working part time and living very frugally might be able to do some tabletop-sized stuff supported by cheap computing. Or maybe they can help analyze data produced from big projects like supercolliders or NASA imagery, with the data distributed via the internet (a worthwhile thing). I'll agree that is a good point. While there may be less fundamental low-hanging scientific fruit than in the 1800s (basic chemistry, basic electromagnetism), there are certainly more edge cases now to explore as the scientific literature has grown in size.
However, given all the complaints already about financial difficulties of full-time adjuncts, as well as the difficulty of newly-minted K-12 teachers getting good jobs, I feel it is still a bit of wishful thinking to thing teaching is likely to support most people who want to do research. Also, in general, research and teaching require somewhat different mindsets and personalities to excel in or be happy in -- which is one reason so many college students get not-very-good teachers who are researcher wannabees (even ignoring self-education vs. teaching).
The main funding issue in the USA is competition and expectations relative the the vast numbers of PhDs being produced as opposed to the 1950s-1960s numbers and available funding then. Yes there are resources out there for science even now, as you say. But, saying the average bright PhD (or non-PhD) can get them is like saying you can take a job at Google or IBM because they have a lot of resources to use for your project without realizing there is a lot of competition for those resources even if you can get in to such a company. Yes, you might win the lottery, and people do every day, but is it unlikely relative to the number of players. IBM Research, for example, at least when I was there, has many people with many good and creative ideas, but IBM will only pursue the very few ideas with the most profit potential (generally measured in billions of dollars), discarding the rest (which frustrates researchers to no end, even if they may sometimes get to publish something before being asked to move to some new project). I read about that frustration even from a book from around the 1980s on researchers -- that people can be asked at a moment's notice to drop their project and do something else and never be able to work on the project again.
The bottom line is that, increasingly, many people are not being given accurate information about career expectations when they pursue PhDs. Although this is increasingly true for much of academia. Which suggests a bubble is about to burst...
Example from Greenspun:
"The average trajectory for a successful scientist is the following:
age 18-22: paying high tuition fees at an undergraduate college
age 22-30: graduate school, possibly with a bit of work, living on a stipend of $1800 per month
age 30-35: working as a post-doc for $30,000 to $35,000 per year
age 36-43: professor at a good, but not great, university for $65,000 per year
age 44: with (if lucky) young children at home, fired by the university ("denied tenure" is the more polite term for the folks that universities discard), begins searching for a job in a market where employers primarily wish to hire folks in their early 30s
This is how things are likely to go for the smartest kid you sat next to in college. He got into Stanford for graduate school. He got a postdoc at MIT. His experiment worked out and he was therefore fortunate to land a job at University of California, Irvine. But at the end of the day, his research wasn't quite interesting or topical enough that the university wanted to commit to paying him a salary for the rest of his life. He is now 44 years old, with a family to feed, and looking for job with a "second rate has-been" label on his forehead.
Why then, does anyone think that science is a sufficiently good career that people should debate who is privileged enough to work at it? Sample bias."
I'm also reminded of a recent discussion of how even a newly-minted PhD in computer science could not get a programming job or find a research job...
Is some good science possible on a shoestring while living in poverty? No doubt. Maybe that is even easier than it ever was, as you point out. But that sort of life is far from the expectations most people have when they pursue a PhD -- especially for people who hope to raise a family. As Greenspun points out, is it any winder that most smart women avoid science as a profession given the financial reality?
BTW, good luck getting independent shoe-string research published in big journals. :-) Although, with blogs and such, again supporting your point, more outlets are possible for new ideas or research results. While I don't know of the scientific merit of these, the "H-Cat" and the "Martin Fleischman Memorial Project" both related to LENR (cold fusion) are examples of a more open source approach to table top science:
One might also see the numerous experiments innovating in 3D printing and open source software and open source robotics as more examples of the sort of things you suggest.
Personally, I feel part of the solution is a "basic income" for all. Then anyone who wants to live like a graduate student and do small-scale science (or data analysis) can do so without needing to find an unrelated job (and also without having to be "credentialed" in a discipline -- see "Disciplined Minds"). I feel with a basic income we would see an enormous increase in human-scale ideas to build a happier healthier world than the ideas being produced by big money. Whether corporate big money, philanthropic big money, or governmental big money, it all tends to come with big strings attached related to building monopolies (e.g. Facebook, Big Pharma), aligning with the beliefs of rich donors enmeshed in the current socioeconomic system (e.g. Gates Foundation, Koch brothers), or supporting partisan power-centralizing politics (big agriculture, big military, big medicine/insurance, etc.).
Having said all that, my life and my wife's for the last couple decades (since grad school and even before) has been some mix of doing our own small-scale research-ish science-related projects (like our garden simulator or other simulations, thinking about triple stores and knowledge representation, or now stuff on stories and social science-ish things), working for others on mostly unrelated stuff, and raising a family (including homeschooling -- which is very expensive in opportunity costs). Ever cheaper computers and communications have indeed made that easier over time. For example, I write this on a US$250 Chromebook for example, whereas my first Commodore PET system with dual disk drive and printer cost about US$7K in today's dollars given inflation and is no comparison in capabilities, especially regarding communications and remote data sources. So, it is possible to do what you say, but it has been a stressful difficult thing for us, even with two bright people and some good luck and reasonably good health. It gets harder as you get older (competing with younger people for those unrelated jobs) and no doubt also if you have more kids.
With trends towards automating more jobs including "teaching" (via software) and even "research" itself, I would expect such a path would get only harder financially in years to come.
Here is one example of the new uncomplaining post-doc that human PhDs will have to compete with: :-)
"As a prototype for a "robot scientist", Adam is able to perform independent experiments to test hypotheses and interpret findings without human guidance, removing some of the drudgery of laboratory experimentation. Adam is capable of:
* hypothesizing to explain observations
* devising experiments to test these hypotheses
* physically running the experiments using laboratory robotics
* interpreting the results from the experiments
* repeating the cycle as required
While researching yeast-based functional genomics, Adam became the first machine in history to have discovered new scientific knowledge independently of its human creators."
It comes down to the question of what sort of society do we want to have of all the possibilities? Marshall Brain's "Manna" shows two extremes. For the most part, so many people have had their head in the sand for the past couple decades since Dr. David Goodstein made his (mostly ignored) points -- including in testimony to Congress in the 1990s (when he was Vice-Provost of Caltech). But I'll have to concede to you that even though over the past couple decades some things have gotten worse about the ease of doing research and development in the USA, some things have gotten better.