> More likely that the companies that institute this will hemorrhage talent that is offered a better deal by competitors.

Won't work when the market colludes. And Silicon Valley Big Tech already got caught in such a cartel - see [1], debated back then in [2].

[1] https://www.latimes.com/business/technology/la-fi-tn-tech-jo...

[2] https://news.ycombinator.com/item?id=10168214