Unity doesn’t give out perpetual licenses any more, it’s a subscription model. If you don’t like it, you can leave at any point in time, but then you also don’t have a license to distribute their engine along with your game.

The problematic part (for Unity) is that they used to have a clause in the contract that said that you could keep using the old license terms as long as you didn’t update the engine. They removed that last year, but developers who are using an older version than that should be able to have a chance at the court. The problem is just that small indie devs don’t have the money for this multi-year legal battle.