> In my last job (Dept. of Energy lab), I used to think it was hard to find people because the pay wasn't good enough, but in my current gig in the financial industry, we're willing to pay basically whatever it takes to get the best talent, but the pool of great candidates is very, very small.

I see lots of very high job requirements (postings at least) for comparatively low pay all the time. I am sure that is part of it. I would imagine at a financial institution (assuming postings actually mention decent pay) the HR gauntlet would turn away a fair share of well qualified candidates for various "check the box" reasons (missing a certificate of some kind, collegiate degree, etc, etc).