Really, Apple is anti Nothing and pro only one thing: money. Everything else is a corollary. Including ease of use, freedom, and privacy. It's just that those things do matter to me (and GP).
Edit: It would massively increase the usability, allowing any apps to be installed, not just Apple approved apps, making the phone more usable to many people. Back in the day I had to buy a dev account just to load an emulator I wanted to use (it was open source) without rooting.
If they ever do offer sideloading/gatekeeper, it should be turned off by default and turning it on should make the risks crystal clear with a scary alert and passcode prompt. Average folks should be heavily discouraged against using it. Gatekeeper works on the Mac, but iOS devices are both far more numerous and far more personal, so the stakes are much higher.
I know the risks, I want to do it anyway. I don't want a nanny over my head.
For that reason, societies tightly regulate car ownership and driving. More so than phones: I don’t need a license to use a phone, nor do I have to register my ownership or have it regularly inspected.
But technology these days has this same characteristic: Others bear the costs of your decision. Every device connected to the internet is a DDOS vector.
I don’t want you deciding whether to keep your device up to date with the latest security patches, because if you (and a few million others) don’t, GitHub is down for me.
Anyway, if you don't want to deal with how an iPhone works, how about buying a different phone.
You can compile and sign (and, AFAIK, upload to the Google Play Store) an APK on an Android device, using AIDE and perhaps other dev toolkits. No computer needed.