The biggest problem for many people is not the %, but the rules and limitations of the platform that comes from Apple being the intermediary between devs and users.
For example, game streaming services should exist on the app store. It is preposterous that apple rejects these apps. They are actively harming thier own platform, making it less featureful by doing this.
Being this intermediary is both a pro and a con for both devs and users, but they disallow anyone else to innovate on the platform. If Apple is so confident that their IAP is what users prefer, then they should give users (and developers) the choice and let the market speak!