In my day, the IDE/compiler weren't free (~50% the price of a new computer), the OS wasn't free (~10% the price of a computer, for each update), account handling was such a mess for everyone that I bought software with an actual chequebook and when I cashed in my Kagi* account they sent me an actual cheque too, and the only way to do subscriptions was a direct debit that wouldn't work in every country. Also lots of American companies wouldn't sell me software directly, I had to get friends willing to do the transaction for me and give them money for it.

I'm not saying Apple is entirely fair or well priced (although they were back when the App Store was new, the world changed around them) but I am saying you'll save a lot less than you're expecting to when you do all this stuff yourself — and I'm speaking as one who has.

Keeping track of 190 different sales tax rates is, even by itself, not fun. Best to offload what you can — same reason loads of business go to "the cloud", use site builders or wordpress, or contract out to third-party payroll services.

* payment processor, not search engine; same domain, otherwise completely unrelated.

It's clear that app and game developers don't want Apple's App Store to charge the same kind of platform fees that Google Play or the Nintendo eShop charge.