You only mention math, coding and videogames.
They already hire and pay people with research titles for creating and solving problems in their fields.
And a lot of labs say that RL can help everywere and has plenty of way to go.
Correct. You can look at the AI tutor jobs in the job board of any of these companies.
RL can do behavior cloning, but really needs good simulations or verifiable environments to get to superhuman levels. That currently exists for math, coding, and a lot of videogames. Soon there will be good enough simulations for robotics.
There's a lot of domains where that simply isn't the case (like bio)