I wonder about that. There'll be a motivation for companies to defect.

If I can get awesome people to work at my company just by offering them a reasonable amount more than at Evilcorp, I'm just gonna do that. If it forces Evilcorp to raise their wages, then that's good for me - EC is spending more to get what they'd get anyway - and if they come work for me then that's good too.

Wage fixing, is a problem, don't get me wrong. However, it's a problem regardless of how efficient you are in hiring.