I don't see developers dropping their price now they can use their own payment processor. All I see is me, the user, having to struggle through using their janky home-made payment processors as I pay and/or try to end my subscriptions.
It's possible they could use the difference for promotion too. In the PC world there's things like nexus.gg that I've been seeing more of lately. It allows creators and streamers to set up a game store so you can buy from them and the creator gets the (rough) equivalent of Steam's cut.
That's a much better model IMO. The creators and streamers are actually promoting your product to a core audience that's likely to buy, so they're more deserving of that big cut. For example, the YouTube channel where I learned about that is from a creator that plays the style of games I like, so their nexus.gg store is actually pretty good as a discovery mechanism (for me).
So smaller developers can keep uniform pricing, but leverage other forms of promotion where the people that are actually driving sales benefit instead of some rent seeking middle man like Apple or Google.
That's not some "janky home-made payment processor" either. I set up an account with the primary platform (nexus.gg) and I can buy from / support any creator curated game store I want within that platform.
