Interesting article about a controversial issue. If merit pay doesn’t improve scores, it also doesn’t make them worse. I think the issue is more about recognizing the best teachers and motivating those who are underperforming.
The best in any field are not necessarily the best paid. Drew Brees is not the highest paid quarterback (but is arguably the best in his field), the best lawyers are not necessarily the highest paid, etc.
Sometimes those who provide the most effective experience and are the most valuable are not the best paid or rewarded with cash incentives.
As with most challenges, there is likely no one solution. Unfortunately, when we talk about public funds and the distribution of those funds, we are talking politics.
Maybe states with the better scores should get extra electoral votes :)