Do they see such performance differences, or does the carrot need to be at least so big to tolerate the manufactured pressure and mismanagement at these companies? An engineer worth their salt doesn't have to work at a given company after all, and more often than not it's the golden handcuffs that are keeping them there as opposed to moseying on over to the company across the street. While underpayment is often seen as a sign of exploitation, large salaries can indicate such an environment too.

There's definitely a threshold of talent you need to cross to be eligible, but beyond that your differential impact is likely to be negligible at least at a company beyond a certain size.