Smartphone game stores aren't the only option for game developers. They could go with Nintendo eShop (30% platform fee), or Sony PSN store (30% platform fee), or Xbox store (30% platform fee). Hmm, maybe there's a trend here?

More seriously, Android does allow sideloading and alternative game stores. There are also subscription services like Xbox game pass, Amazon Luna, and Apple Arcade, though I don't know their exact payment models. And PC gaming still exists - there are popular game stores like Steam that take a smaller cut.

I think it's hard to make money on games on any platform, but Steam does seem to have a vibrant indie game scene.