As someone with a PhD in Immunology, I couldn't agree with you more. While an undergraduate in the 1990s, quite a few of my classmates who were graduating with a BS in Biochemistry left for non-science professions such as banking and consulting because the pay was much better - those that 'remained in science' were mostly pre-med. Of my friends who left science, all were making over $100,000 per year before I finished my PhD. Of my friends who remained in science, all were making well under $100,000 within five years - though that's a bit unfair since the average pay for a graduate student was ~$20,000. Those who left immediately for industry were making around $50k after five years.
I attended a graduate program at a top university (the Immunology program is consistently ranked in the top 10), and of my class only 2 out of 9 (includes me) continued on for a post-doc. The rest went into scientific writing, consulting, teaching, and most into law. With the exception of Biophysics, my friends in the Biochemistry, Cell Biology, Microbiology, and Genes and Development programs report similar experiences. Some of the reason for leaving science was burn out - low pay, long hours; not to mention everyone knew that a post-doc position was worse (which is very much a sink or swim environment). Pay for a post-doc ranges anywhere from $40k - $50k, with no retirement in most places. A post-doc is about a 5 year position, though many people do two post-docs. In comparison, everyone of my graduate school classmates who went into consulting or law were making well, well over $100k per year, with better work hours, with retirement, and with vacation. FYI, as a post-doc, at a top institution, in our three lab group we had 37 post-docs, 4 staff scientists, and two graduate students - 32 of the post-docs/fellows were foreign (though several had received their green card), all 4 of the staff scientists were initially foreign (two green cards, two citizens), and one of the graduate students were foreign. Some of the post-docs/fellows stayed here in the US, some left. The Ph.D. tend to stay, the MDs tend to leave as they can't practice medicine here without a residency.
So you stick it out, worked your 80 hours per week (seriously - it's not forced, but you're competing with the world), and happen to have a Nature, Science, or Cell paper. Let's say you get hired as an assistant professor (for the record, there's nothing 'assistant' about being an 'assistant' professor - it simply means you haven't gone up for tenure review yet. An associate professor is tenured). Pay can vary wildly at top institutions, but starting pay is $90k - $110k per year. This is at a top institution who are recruiting the top post-docs, teaching colleges and second tier research institutions pay less. Industry pay tends to vary quite a bit, but the quality of the people and the positions vary quite a bit as well (the range I've seen is ~$60k - $125k per year. The work hours get better, but not by much (especially before tenure).
For science you have $20k of 5 years of graduate school (no retirement), ~$50k of 6 years of post-doc (assuming only one post-doc, not a safe assumption... oh, and usually no retirement), and you manage to get a top faculty position... $100k. Average age of first faculty position is ~40 (younger if you're foreign by the way given the differences in the educational systems), while working 60-80 hours per week. Compare with all of my peers that peeled off into consulting, law, banking or business who were making far more, far sooner, with vacation, with benefits, with bonuses, with retirement, with a better work schedule the choice is clear. With that said, I love my job (and in fairness, my peers who left science love their jobs), but I'm certainly not encouraging my children to go into science.
"No, no, I don't mind being called the smartest man in the world. I just wish it wasn't this one." -- Adrian Veidt/Ozymandias, WATCHMEN