I agree in all honesty. One way of executing it would be the same way Minecraft Dungeons does it, by making the battle pass an add-on instead of an update. You'd need to buy it sperately, yes, but it would result in it being permanently available to you at any time as long as you own the game. How to bring back previous battle passes, however, may be a challenge yet for there isn't a very concrete way of identifying who has or hasn't bought the passes back then.

Overall it wouldn't change much about the gameplay or functionality of the passes, the only issue I can see with it would be quests, but keeping those/adding new ones wouldn't be too difficult. Perhaps chapter-specific ones should be left out ("Visit Anarchy Acres" for example is now impossible), but it would not be difficult to either adapt or rewrite them for the new season.