Too many openings?
Too many engineers working for themselves?
Too many engineers retiring?
Too many engineers going abroad?
Too many engineers interested in the same small number of niches that leaves everyone else with too few applicants?
...?
> Too many engineers going abroad?
I don't think this is a contributing factor. More software is getting made/integrated than ever and the talent pool is inelastic; programming is "hard" and "boring".
I would argue that the talent pool isn't completely inelastic, but it does take a number of years for the talent pool to respond - especially because the most acute shortages appear to be in the market for senior-level developers.
With that in mind, I think "recovered" is the wrong word: since enrollment back there was inflated with people just interested in a good salary, nobody in CS really wants that to happen again. As one of my professors would say, that's what the business school is for. These days there is quite a demand on the major, but I think it's actually mostly from people genuinely interested in the subject.
So, purely anecdotally, my observations echo yours: CS enrollment has increased, but not to the levels of the dot-com bubble.
I expect after 2003 or so, that bloc nearly vanished.