> they're artificially constraining their supply of candidates and increasing the cost they need to pay for developers for absolutely no reasons.
The incorrect hidden assumption is that by decreasing your own supply the value goes up.
It's well known that turning down candidates or refusing to interview them sends the message that their skill are less valuable. It's HR management 101.
The same goes for "anti-poaching" agreement. If FAANGs don't hire from each other they reduce the number of high-paying employers willing to hire the average FAANG employee, effectively reducing average salaries.
On the contrary, rejecting a high number of candidates pushes market rates down.