It depends a lot on the developpers' initial situation I think.

Developping for iOS before getting hired usually means paying for both an Apple machine and an iOS device. If you already had both that's a non issue, if you were on android + windows that's a tougher gap to cross.

> Swift + UIKit vs HTML + CSS + JS + framework

It's personal preferences mostly, but I think Swift is tougher to beginners that Objective C was, and requires more upfront concepts to be fluent. I'd call it a wash compared to HTML + CSS (which are not simple by any way, but there's much better tooling to understand how it works)

I imagine there is much less demand for iOS developers than general web developers though, so maybe the ease of entry makes the calculation different.