Needless to say, my report took on a rather more morbid tone following this, but at least I never lost my interest in space.
1) I care because a lot of guns are acquired by criminals from honest people, either knowingly/negligently (gun shows without background checks being the obvious example) or inadvertently (lost/stolen). Reducing the legal boundaries of plastic/undetectable guns means that there are going to be fewer of these and a correspondingly lower probability these guns will be widely distributed or used.
2) The "if a criminal really wants to" argument assumes that all crimes are carefully planned and executed, when facts show otherwise. Statistically, most crimes are unplanned, opportunistic, and random. The chances of all kinds guns (plastic/undetectable being one subset) being used is lowered when access is reduced. Again, facts and statistics bear this out in places where gun control limits access and there is correspondingly lower rates of run related crimes.
Overall, bans like this do have a simple, logical effect of reducing crime. In concert with other measures, laws in general reduce the probability of potential actors from simultaneously having the means (anti-organized crime, gun bans), motive (anti-poverty measures, education, penal), and opportunity (police patrols, security systems) to commit crime. No single thing with STOP all crime for all time.
Those aren't Commandments, those are your (mostly incorrect) interpretations of them.
--says me and my interpretation
Sometimes corporations fail: when coordinated behavior is required, for example in cases of large externalities. The economics classic "Tragedy of the Commons" is exemplified by our modern day causes of and solutions to pollution (compare for example how acid rain and CO2 are/are not handled). Game theory and showed us how under real world economic assumptions and actors (not the economics 101 supply/demand model that many people never seem to advance past), markets can and do consistently fail without regulation.
Also consider what is efficient. Sure, society, life expectancy, technology, or anything can probably advance without governmental institutions (or week ones), but much faster with properly designed strong interaction much faster. As a thought exercise, consider the relative course of history with and without the CDC, WHO, and UNICEF. Go read about guinea worm disease if you need help. You seem to like the idea of consumption taxes, a revenue mechanism that is very inefficient since it ignores the declining marginal utility of money.
As an engineer myself, I am dismayed at how many engineers I encounter that don't get the above and are libertarian in nature. They should firstly be interested in designed to solutions to problems, like the various failure modes of market based systems or political institutions. Second, they should understand the dynamics and forcing functions that might drive these very complex systems to self destruction when improperly designed or regulated. Back when I was in school, they made all the engineers in the early intro classes watch the various famous cases of engineering failures...Tocoma Narrows, Hyatt Regency skywalk, space shuttle...They still do right?
(ok, RDR is not that good, but it helps, and I'm sure as this becomes even more prevalent, people will work around it)
But you are unlikely to leave the car out front of your house with the keys in it and a sign on it saying, "Take me!" If you did, you might never see the vehicle again.
I might if I knew that after someone took it, a magical copy remained in its place. And I definitely would if everyone did this, so that cars were essentially shared, I definitely would.
It would be pretty cool...relatively few original cars would multiply many times until everyone had a car. Then, undoubtedly, some would tinker with cars they got at little to no cost, whether for fun, or because of special needs or tastes. Hopefully they would produce better, faster, higher mileage, more luxurious cars...which would then multiply since people would like them better. Eventually there would be a great variety, each catering to individual tastes, and constantly improving too. Some people would almost certainly band together to support particularly complex tinkering, or even wholesale re-creation, where the more casual tinkerers couldn't support, and their needs were great enough. Soon...flying cars, submarine cars, space cars! Yeah...this would be a pretty cool universe to live in.