There are a few technical issues I need to work out before I make the change though. First, I need to get macOS running natively on my workstation so I can install my own software on the phone, as I'm not running out to get a MacBook for this single need. Second, I need a root shell.
Secure enclave. App sandboxing. Fine-grained revocable permissions. TouchID. Differential privacy. iMessage encryption. Find My iPhone. On-device models for photo recognition.
The question is how to spin it in a positive way.
The developer looks at the app sandbox and fine-grained permissions and thinks "I can't run my code on my own device," and walks away.
The police officer looks at TouchID and the secure enclave and thinks "I can't gather evidence," and walks away.
The marketeer looks at on-device models and differential privacy and thinks "I can't understand what my users want if the device doesn't report it," and walks away.
But the user (arguably) benefits from each of these things. App sandboxing, permissions, and a lack of background tasks remove the ability to run malicious code without my consent, in theory. Secure enclave and encryption remove a malicious third party's ability to intercept my communication, in theory. On-device recognition models allow me to benefit from better organization without sending my photos to some cloud vision service, in theory.
I agree that this would piss off developers who value this kind of data robbery - but Apple is in a much better position to double down on selling quality apps that treat their users as customers instead of products than Google (based on the statistic that iPhone users purchase more apps).
There's Ubuntu Phone, KDE Plasma, Copperhead and others but they don't feel like a good solution. The problem is always the same: no apps. It doesn't matter if I can install 99/100 apps I need but the one I can't is a messenger one of my clients requires me to use. Or if I can't really rely on a compatibility layer like MicroG, since Android is not that open anymore.
These OSes exist today, and I'd like to use them, but they're typically limited to a very small handful of (typically obsolete) devices. As long as this is the case, they'll have a lot of trouble finding enough developers and users.
If we could simply link our own kernels against these drivers the way we do with the nvidia driver and DKMS on desktops, it would be a revolutionary step forward for alt smartphone OSes. We could start working on userland instead of spending so much time devising hacks to simply get graphics and radio working one handset at a time. Unfortunately, the OEMs couldn't care less and would much rather our phones become e-waste than eat into next year's sales figures. Until then, we're pretty much at the mercy of Apple and Google :(