upper limits to the number of people who can hold advanced STEM jobs
It's not that there is a limited number of people capable of doing work in STEM, it's that the economy doesn't offer enough jobs in STEM. There have been layoffs after layoffs in chemistry, pharmacology and biotech, math isn't the dream ticket to Wall Street any longer - in fact the only areas with job openings are computer science and petroleum engineering. Computer science is growing because investment there increases workers' productivity, and the jobs in petroleum are there because of domestic gas production. As soon as tech yields no more increases and as soon as the gas bubble pops the party will be over there, too. Eric Schmidt predicts public unrest and wants to get out of the way. A worrying thought.
It's not that there is a limited number of people capable of doing work in STEM, it's that the economy doesn't offer enough jobs
It's quite likely both.
There are absolutely people who can't (or won't) work with technology. And there are those who are qualified to do so who don't have the opportunity. Either way, opportunities for employment in the sector are limited.
I'm old enough to have seen a number of phases in high-tech career trends: highway construction (1950s & 1960s), nuclear power plants (1970s), defense (1960s & 70s) (a good family friend went through the trifecta of these three), consumer tech (1990s, 2000s), and Wall Street / technical trading (1990s - 2000s). Petroleum careers had their dark ages in the 1980s - 1990s oil glut. And there's the boom that never really materialized in biotech, which everyone and his kid brother's dog was pitching in the late 1990s / early 2000s, notably Larry Ellison and Tim O'Reilly.
It's not that there is a limited number of people capable of doing work in STEM, it's that the economy doesn't offer enough jobs in STEM. There have been layoffs after layoffs in chemistry, pharmacology and biotech, math isn't the dream ticket to Wall Street any longer - in fact the only areas with job openings are computer science and petroleum engineering. Computer science is growing because investment there increases workers' productivity, and the jobs in petroleum are there because of domestic gas production. As soon as tech yields no more increases and as soon as the gas bubble pops the party will be over there, too. Eric Schmidt predicts public unrest and wants to get out of the way. A worrying thought.