Both are solved with making marginal gains tax hyperregressive. Said CEO would gain little in either case on his salary. (Making it gains also closes loopholes like getting buildings, deals, land, expensive cars or such.)

Regardless of whether he bargained for it or squashed the employees, someone paid for this gain. With increased productivity they didn't benefit from or with plain old loss.

It probably really is the only way to prevent rich from getting much richer than everyone else and taking it all.