If you want to force Apple to allow different browsers without addressing this problem, then you are trading one company's monopoly on a single platform for another company's monopoly globally. And there is no reason to believe that Google will behave any better than Apple has. It's not like Google hasn't tried to skip the standards process before.
So when people argue that "it's for browser diversity" I have to consider them as 1.) naive, 2.) actually working for Google. 3.) just developers who are tired of being forced to target multiple platforms.
Do I think it's ethical that this is how this stalemate is handled? No; taking away user choice is limiting the freedoms of users.
Do I think Safari is amazing? No; I think Chrome on Android, today, is better than Safari on iOS. I may be harming users today by forcing them on Safari.
Would I fold if Apple only allowed Firefox/Lynx/Netscape? Yes; My problem is with Chrome, not with other browsers. But I think the number of people who genuinely want to Firefox is tiny in comparison to the number of people who would just install Chrome.
My worst fear is that once Chrome is allowed on iOS, then there is no reason for Google, or anyone else, to target anything other than Chrome; and that would ultimately be harder to fix. A year of Chrome dominance, where developers only target Chrome would fully entrench Chrome and make it difficult for anyone to build a browser that wasn't just a Chrome fork that emulated all of Chrome's bugs and unspecified behaviors. The alternate solution, where the Chrome problem is addressed first, then the fix is "just" passing legislation that opens up iOS. One fix involves just changing the behavior of one company. The other fix involves changing the behavior of thousands of companies.
Instead what happens is this internecine warfare where everyone shits all over FF for political reasons (most of which have no relevance to their day to day use of a web browser) and uptake of Tor/Brave is miniscule and most everyone sticks with Chrome.
Why ? Open up the platform first.
1) Firefox cannot compete against Google endless resources m. Google will win, not a matter of it but will.
2) The time it takes to decouple chrome from google will be too long. It may just kill Firefox before any action can really be done.
If you force Apple to open up iOS then Chrome just takes it over and Safari will take such a hit that Apple will probably have to kill it. Then Google will own 99% of the portal to the web.
I think I'm arguing with a bunch of Libertarians though who think that an unregulated market is some kind of magic sauce that will conjure up a Chrome competitor out of thin air, and not a recipe for monopolization.
How much would it cost for them to fund firefox development to make it a stronger competitor?
Okay, Apple: do that. Also open up the walled gardens. You can make it a setting if you want to keep the beginner computer users safe.
Safari only has ~20% market share because it's has ~25% of mobile and nearly 50% of tablet and only because Apple restricts those platforms. If Apple opened up their platform that would vanish and Chrome would take over.
The platform being relevant and closed is the only thing stopping Chrome from becoming the next Internet Explorer 6.
Underhanded? It's pretty clear that your stated goals don't align with your real goals here.
Edit: I have a hard time putting into words why your arguments seem so deceptive to me. It is like whataboutism: the arguments you are making are technically functional but they just completely fall apart with any reasonable weighing of the pros/cons because it betrays the "intrinsic" goals (choice, browser competition, functionality, security) for "extrinsic" goals (browser diversity, but mostly the success of safari). This makes me think that you're secretly misaligned and that you actually hold those "extrinsic" goals as your intrinsic goals.