Earlier quoted context omitted.
> So Apple will be collecting 27% (instead of 30%) for... what exactly? Off the top of my head... - Bandwidth - Running the App Store for users - Marketing the App Store - App review - Security efforts to keep malware off the store - Making App Store optimisation tools for developers There's a lot of moving parts to this. You could argue that none of this is necessary if you sideload, but distribution is worth a lot…
You can probably include development of SDKs and documentation as well.
With limited exceptions, platform vendors (Microsoft, IBM, Sun/Oracle, etc) are generally not in the business of paywalling their development documentation, tools, and SDKs, otherwise it makes their platform far less attactive to third-party developers that they absolutely need in order to.
...and ever and never-mind that Apple's documentation is sub-par[1], even with the billions of dollars they're raking in. It boggles the mind because nothing is stopping Apple from hiring the people it needs to ensure decent documentation and DX, which can be paid-for directly from the $99/yr developer membership fee.