[abecedarius]

I don't know, but I wonder if having so many students here on a visa and hoping to immigrate is one of the main factors. (I'm not against immigration, I'm saying the visa can create a nasty power imbalance against the worker.)

After all, a near-steady-state academic job market is not new these last decades, labor markets should equilibrate unless there's some kind of barrier, grad students are heavily foreign-born https://en.wikipedia.org/wiki/Foreign_born_scientists_and_en..., and many of them hope to immigrate (same source). What changes to the rules would improve the bargaining position of both native and foreign-born workers? (At the expense of employers like this one.)

An alternative factor is people gambling they'll make it big, like musicians and athletes. This must be part of it, though professors aren't rock stars or drug dealers.