3) Arte Moreno is now forced to build a team focused on winning
This is not Shohei Ohtani's fault. The Dodgers are going to be competitive each and every year even with Ohtani's absurd contract because their ownership group doesn't care about the luxury tax. They're willing to do whatever it takes to win, unlike the Angels owner. Ohtani is a winning player that makes any franchise better. It's the Angels' fault that they never won with him.
Arte Moreno likes to toe the tax line but not cross it. He did that to perfection this past season, thanks to the Angels moves after the trade deadline. Moreno likes to sign as many star players as possible that will get the Angels close to the tax line but then never cross it.
If the Angels had re-signed Ohtani, how likely is it that Moreno would suddenly have a change of heart and spend like he should? Probably not likely at all. The Angels can now add more talent around the good players that they currently have instead of just Ohtani and a bunch of Quadruple-A players.
WIth Ohtani around, Moreno didn't have to field a winner to fill his pockets. Without Ohtani around, the Angels will have to find a way to win baseball games to help Moreno make some money. Who knows, maybe with Ohtani gone Moreno will finally sell the team. That'd be the real best-case scenario that most of this Angels fanbase would take in a heartbeat.