NA was unable to compete on the world stage, they only play other NA teams, EU meta evolves without them and they get rekt if they ever play against EU. Add to that that the NA scene was never as big into CSGO as the EU scene in comparison. They were just not getting results, plus no support from orgs. No major=no sticker money=even less reasons for orgs to stay in csgo if it's just to lose money. Also many EU and CIS pros in similar situations also switched to valorant.
Now I'll go sleep, gn and I hope you'll find the way out of the echo chamber soon