When you consider the Pareto nature of app store earnings, Apple's best move was to wait and be forced to make the change.
If I guessed right, Apple's income probably won't go down much. I would rather use Apple payment system. Lots of other people will also. It is simple and allows me one-stop management of subscriptions and purchases. Some folks won't of course, but it is the easiest choice.
The price would be higher if you used Apple payment system. That is how companies would get consumers to be enticed to use other payment systems.
That is what Epic did with their V-bucks: either use Apple system at the usual cost, or use Epic payment system at a permanently decreased cost (20% cheaper in August 2020).
The quote from the injunction is that apps may now provide "external links, or other calls to action that direct customers to purchasing mechanisms, in addition to In-App Purchasing."
You might be in this mindset because up until now almost only apps that nicely fit Apple’s rules have stayed in the AppStore. I hope this ruling and subsequent changes will being in more services that made no sense before but can at last come into the AppStore with their payment system.
I see this ruling as basically Apple forced to give everyone the same position that Netflix had to bargain hard. I actually hope this will be positive for Apple, with more activity, better user experience for their platform.