I read an analogy years ago about how stupid the logic behind most promotions in software are. Think about a sports team..
"That guy is our best player! He scores more points than anyone else in the team by far! Quick! Let's pull him out of the game and make him the coach!"
Why not keep him in the game and just look for someone who can be a good coach?
Difference is that on a sports team, you are under contract to be a player and there's not really any chance to just be promoted to being a coach.
If you have a high performing dev who wants to be a team lead and you hire someone else for that role, you risk demoralizing them and causing them to look elsewhere.
Morale is important. Promotions, real promotions with more responsibility, are important
"That guy is our best player! He scores more points than anyone else in the team by far! Quick! Let's pull him out of the game and make him the coach!"
Why not keep him in the game and just look for someone who can be a good coach?