It's easy to understand, they're struggling on PRO CS, can't win any tournaments and make any decent prize money.
Valorant comes as a good solution, every team is new to the game because the game is new, with their acquired 5v5 fps skills they'll have a little edge over the other Non CS Players. Here they will be the best and it will be possible to win games and tournaments.
The best teams on Valorant will probably be full of pre/CS players that didn't have what it takes to win on CS. Like ScreaM.
If the best aren't playing this game, they'll have a chance (win games/win prizes/win Money).
This is the main reason. --> Because the game is worse.