That is a very good point. On the other hand there are a couple of other factors that might be at play. There is the Apple Tax of $99 for a developers license as well as requiring a MAC in order to develop an App. Perhaps not a big deal.
There is also Apple's policy against taking in App purchases without paying Apple a percentage (is it 30%?). This is the reason you can't use your Amazon Prime Video App to buy a movie - Amazon does not want to pay. Apple cannot enforce this rule against PWA's.
I think Apple benefits from this in two ways: first it encourages the 30% payment, and in the cases where companies won't pay (netflix, amazon prime for example) it provides a barrier that makes their own offering more attractive.
The Mac in its entirety is less than 10% of Apple’s revenue. The number of people buying them just for iOS development is even smaller.
You only have to use Apple’s in app purchases for digital purchases. For instance you can buy physical goods in the Amazon app.
Most digital content providers are already forcing you to buy via the web. The only app that I can think of that still supports digital content that you buy in app like books, videos etc is Udemy.
I doubt anyone chose to buy AppleTV+ over Netflix because they had to go to a website.
There is also Apple's policy against taking in App purchases without paying Apple a percentage (is it 30%?). This is the reason you can't use your Amazon Prime Video App to buy a movie - Amazon does not want to pay. Apple cannot enforce this rule against PWA's.
I think Apple benefits from this in two ways: first it encourages the 30% payment, and in the cases where companies won't pay (netflix, amazon prime for example) it provides a barrier that makes their own offering more attractive.