(Disclaimer: I've been involved with OWA for a little while, my opinion and especially wording below is my own but, in large, it should mostly cover the OWA standpoint regarding these matters)
Reading through the comments, I noticed a certain theme / line of thought that keeps popping up when we argue for browser competition on iOS (which is actually not the only thing we have opinions on

)
- Allowing 3rd party browsers on iOS will allow Chrome to become dominant
- Or: Apple is preventing a browser engine monoculture
- Related: Web developers just want to build and test their sites for one browser
First of all: none of these arguments are made by Apple (afaik?) as to why they only allow WebKit-based browsers on iOS. They point to privacy and security as the primary reason. Seeing how Safari security bugs take the longest (and a full OS update) to fix when compared to other browsers - and that these bugs affect every single iOS user, no matter which "browser" they use - this argument can be quite easily dismissed. The CMA, for example, already does.
Apple is certainly
not the steward of browser competition and diversity (that's Mozilla's job

). They are, in fact, quite the opposite. They enforce a browser monoculture on an entire platform that has up to 50% mobile market share in most western countries! No other major general computing device prohibits 3rd party browser engines. Meanwhile, they seem to starve the WebKit team from resources needed to compete (or even keep up).
Then on to the argument(s) as described above:
Our hope is that allowing competition will create incentive for Apple to actually compete and invest in WebKit so users want to keep using it even if there are alternatives and developers want to support it because it's a great browser.
Many macOS users use Safari (power of the default + it's actually a nice browser - from a user perspective, at least). Safari has unique selling points. And again, it's the default.
We actually want more browsers on iOS like we have on every other general computing device, not less.
For developers, supporting WebKit is quite a pain right now. You have to own a mac and at least one iDevice to debug any of the many bugs Safari will throw your way. When Apple is forced to compete they will hopefully fix many of the current bugs, add features and improve the dev tools so devs can more easily debug those bugs that remain.
There will always be sites (especially highly specialized web apps) that require a certain browser because they rely on a specific feature that no other browser (yet) supports. This is already the case right now. If WebKit catches up, the chance that a site requires specific browsers should actually decrease. If WebKit ends up ahead (as it once was, Google chose WebKit as the basis for Chrome for a reason), it will be the browser that the web app will target.
I also noticed how quite a few Firefox users are choosing Apple's side, often times citing the Chrome monoculture argument. It strikes me as odd that people who use and/or work on a browser whose mission is to ship an independent alternative browser engine argue that it's a good thing that WebKit is the only engine allowed on iOS. Shouldn't they want a full Firefox browser on iOS?
- OWA is pushing the Chrome agenda
Again, we want more browsers on all platforms, not less.
We want more choice and we want that choice to matter. For example, we also strongly oppose apps like Google Search (on Android) and OSs like Windows 10/11 not respecting default browser choice. We oppose apps like Facebook making it hard to open links in your default browser.
It may seem like we only target Apple, but please believe me when I say we're not. The iOS browser ban
is the biggest issue we would like to see fixed ASAP, but it's far from our only goal.