Is revenue per employee the best metric? Productivity gains don’t automatically justify higher executive pay. Most of those gains come from technology the CEO didn't invent or personally implement, supply-chain leverage, and cost-cutting at the bottom, not from some surge of genius at the top. Yet the financial rewards are heavily skewed upward, while median wages flatlined. Plus you know the rule about what you measure being what you get more of. All that would happens under your metric is CEOs push to move to 'contractors' to reduce the measured headcount to justify an even higher salary.
Changing the metric just masks things. Society is broken for those at the bottom, and if their numbers grow too large, it will become broken for everyone.