Yes, it does mean that you have to use them (if you already do). If you're a user of Spotify or Tinder and they pull out of the App Store, you now have to follow whatever arbitrary consumer-hostile decisions that will make them the most money since there's no one to tell them otherwise. I like that they have to follow the strict rules in the App Store because I know they want that sweet sweet App Store money and won't pull out unless there's a less strict option. It's like giving auto manufacturers a choice to either sell via dealerships that follow EPA laws or those that don't. Gee, I wonder which one they will go with given the choice?
Forcing you to use 3rd party store for few apps is somehow worst than forcing everyone to use the Apple store for all apps?
This discussion is moot. Apple only has to lower it's cut to cost + a reasonable markup instead of abusing it's position to charge 30%. Then everybody can be happy.
It's not going to be a few apps and they might not even be a few stores. It's going to be a bunch of stores with varying rules and conditions and bars for quality and selection of apps. I'm not interested in that because I don't trust other companies to do the right thing. If you're interested in that, you can use Android. No one is forcing you to use iOS.
Also, there is no reason to believe any percentage is too high or too low. 30% is what Apple has charged since day 1 when it had no position whatsoever. You will need to explain exactly at which point in time 30% became problematic.
I think it's getting obvious that the situation is untenable. If it's not the US courts, some other court will likely enact changes.
In the end it doesn't matter how Apple and Google got to this duopoly position of power, if it was fair or of they had to work hard. The fact that matters is where they are now.