I doubt we will ever be able to "measure" the effect. We can only guess and debate it with hypothetical scenarios -- "what if all these CEOs had had to compete for talented employees, instead of fixing the market for them?"

Regardless of the effect, it is a shame to see that these leading CEOs, who for years have vociferously complained about media & telecom oligopolies for preventing competition, were for years simultaneously using their oligopoly to prevent competition for employees.

Apparently, they're all for free markets, except when it affects their bottom line!