Because it’s a relatively insignificant market? However it’s pretty remarkable that Apple only makes a few billion less than Visa from its AppStore despite of the processed amount being 100x+ lower.

I guess the problem with the 30% is that it seemed like a very good deal for developers back in ~2010 compared to all other options.. but well it there is no incentive to lower it even more since there is no competition

Then again Steam and GOG for instance can still take 30% despite operating on perfectly open platforms so they must provide some value.