Going in a different direction, you could also look at the state of Windows malware (and adware, eg toolbars) as a potential outcome to the un-walled garden approach: you end up with malware and thus the existence of an anti-malware industry.
It's why I like(d) Linux and Mac OS X (macOS) as well: I can set up my parents with a non-admin default account on their system and not worry too much about them hosing things too greatly (especially with off-machine backups). Windows caught up with that paradigm eventually.
If sideloading comes to iOS I hope that a similar mechanism is introduced: not just "please confirm" dialogue and/or Touch/FaceID pop-up, but a separate 'login'.
But yes, the safeguards that prevent sideloading today make me confident in recommending an iOS device even to someone that downloads malware anytime an ad shows up promising free gift cards.
I'm happy that GPG/PGP etc. are a bit difficult to use, because it makes the IQ threshold necessary to coordinate nastiness secretly a bit higher.
Remember how great the blogosphere was prior to the advent of social media? Social media made "blogging" a little more accessible and it became a cesspool. Speed bumps can be a very good thing.
There is research on this in the field of existential risk. I don't remember where exactly but it's formulated as the number of people one person can kill with easily accessible products. In particular biotech is becoming more and more accessible, which great, but has a big impact on that index. There is a great defcon talk by a doctor working at Intel I think.
And? If they're using (say) Signal or even Messages, it's already end-to-end encrypted and there's nothing Apple can do about it.
> Is that really the world you want to live in?
You mean like they're able to use GPG/PGP, Tor browser, and Tails Linux distribution to potentially have secure encrypted communications now? Terrorists, drug dealers, pedophiles, and organized crime have been the boogeymen against strong crypto for decades:
* https://en.wikipedia.org/wiki/Four_Horsemen_of_the_Infocalyp...
We've been through this before in the 1990s, and the techies (who tend to often lean libertarian) have generally sided with opening things up even if that meant the baddies also got the same capabilities:
* https://en.wikipedia.org/wiki/Crypto_Wars
Coming at it form the opposite end: should the IETF weaken TLS with backdoors so the government agencies can monitor the bad people? Is that really the world you want to live in?