I doubt that has anything to do with getting "large in terms of job applications" alone. It's a correlation, alright, because wealthy families have it easier to get high-status and high-paying jobs for their kids, and if such a field grows, wealthy people flock to it like everyone else. But I sincerely doubt you'll find the wealthy over-represented in physical labor / blue collar jobs, regardless of how the ups and downs in the labor market for those occupations.

The way I see it, it's like 'swatcoder and 'lovich said upthread: the field became a money printer, and attracted - not revealed, attracted - a different kind of people, with a different mindset. I too saw this change happening. Applicant pool size? That's a spurious correlation - it's just driven by the same factors that make software industry a money printer.