Because this is the half Apple broke off to sell as iOS apps. A domain that is entirely exclusive to apple, and requires all sorts of hoops to gain access to (including purchasing Apple specific hardware).
Further - they enforced that domain by strictly locking down down the capabilities of literally ANY browser a user might try to install on iOS. Because otherwise users might have chosen to use a progressive web app and Apple wouldn't get their fucking 30% store tax.
The problem isn't that other clients exist, a company that wants to have complete control of the UI can make an App that ensures it, they can deep link into it - no problem.
The problem starts when the main platform used to consume the web starts having specialised features which make some websites work only on this one platform because the developers build specifically for this one platform.
And no, this is not the same for the AppStore because the AppStore is not the web. Apple controls a minority share of the market, its not universal and it's not supposed to be universal - its a an additional distribution channel of content to Apple specific devices.
The "App Store" might look like a website to you but it's actually what we call a "native" app, which means that it's not a website at all but a computer program that runs on your iPhone if you have one.
Divided them, if you will. Made it so that there is a closed system of software that only users on certain "approved" hardware can access and use, and also locked those users into that system by preventing real competition.
I certainly am unable to see how that is entirely related to this conversation. It's a real puzzle to me...
Gosh, I'm so silly. I hardly even noticed that the web is also a distribution platform for perfectly acceptable applications. They come with their own code and logo and everything! They even... wait for it... run locally on your iPhone if you have one!
Except they don't do it so well on iPhones - because Apple refused to implement or support a bunch of features that might have threatened their revenue on their app store. Which is fine, but then... they also stopped ANY other developers on the planet for being able to do that work on their platform.
They sure are nice fellas, those Apple folks.
Did I mention their app store is also an internet site? Literally. It has to be. Apple did a shit job making the HTML view, but the whole fucking shebang of a platform is delivering content to users over... the internet. Through a website.
They just locked the UI their users see for that content down to something they call "an iOS app" which is really code for "We turned your general purpose computer into a less general purpose computer for you!"
Which... is exactly the same fucking thing Google is doing now. Making my general purpose computer less general.
You do understand that a browser is an application?
And that Apple cripples literally ALL of them on iOS to push devs to their own non-compatible app ecosystem?
How in the ever-loving fuck is that not dividing the web in your eyes?