It's a lot like employee pay, actually.

You can guarantee poor performance by paying too little. But beyond a certain point, more pay does not create better performance.

When finding that inflection point is a matter of politics & ideology, you might as well give up and go drinking. And no, I do realize that it's NOT actually a matter of politics and ideology, that data can show where that point is. But nobody in charge is ever going to listen to that data, so...