Stock buybacks are the indirect rule, it wasn't even allowed for most of the existence of stock markets, it's the odd one out which created perverse incentives.

It's not about regulating executive compensation, it's to close a gap that was opened and only led to poorer decision making at the executive/board level, there's no advantage to the company. It's a stupid instrument with no reason to exist except to return money to shareholders in a way they can avoid taxation events.