I too think it's preposterous that it's somehow okay for companies to simply make disappear things you've bought/spent money on/anything like that.

This is the main reason I avoid games like this. It's just a trap, nothing keeps the developer from retiring the game whenever it feels like, nothing keeps the developer from releasing an update that completely changes how the game plays. If you like a game now, next week they can rebalance it and introduce microtransactions and that's... perfectly okay it seems?