Earlier quoted context omitted.
I agree, and frankly it’s been obvious since its inception that uikit is a better appkit written with the benefit of experience - more limited at present but suitable for all devices. They should have started this years ago and have a unified platform with tweaks for different UI. Bizarre doublespeak in the presentation though as they denied this was the plan - explicitly said no merger.
It's not doublespeak, it's very clear refutation to those who fear macOS fading away and being replaced by a locked down, ARM-powered iOS laptops, Apple machines turning into alternate version of Chromebooks. The message reads to me as "we're bringing the good things from iOS over to macOS, rather than abandoning macOS and replacing it with iOS".
"Are you merging iOS and macOS?" "No."
Then proceeded to detail the port of the iOS APIs to Mac and some apps just using those APIs.
Time will tell, but I think a merge is exactly what they are planning long term, and it makes sense to do so (with some differences for user input and larger screens). It's crazy to develop very similar APIs for GUI apps in parallel, and what has become two different OSs with slightly different apps and feature sets, but a huge amount of overlap. The savings for Apple and developers of having a consistent set of new APIs and one set of apps to manage (for example their entire office suite) would be huge.
The sheer pressure of money and users on the iOS side means that will be the dominant one, and UIKit will win.
Re lockdown, that's more a political decision than a technical one, it could go either way, I suspect both platforms will become gradually more and more similar (they already are converging) and the future will be close to the one you fear, with at the very least some ARM powered locked down laptops (which I'd be very happy with).