So far the Dodgers have won one championship with Betts. If the Dodgers win 2 or 3 more with Betts, then I believe the Dodgers' FO will say it was worth the 12yr/365mil contract. If the Dodgers don't win another championship or even if they win one more, they may believe it was a bad move.
The SOX won one championship with JD. Does that make his 5 year contract worth it? I say it does.
Big money is spent on players to win WS, not to just have the best regular season record.