They have a monopoly on devices running iOS apps, and a monopoly on channels to deliver mobile software to anyone who uses an iPhone (i.e. either their App Store or Safari).
So Does GM have a monopoly on Chevrolets? Does that mean they can be regulated as a monopoly? Chevrolets compete with Fords and Mercedes and Honda, etc; so having a monopoly on your own brand is not a monopoly. I have both an Android phone and an iPhone, so when I hear that Apple has a phone monopoly it just seems like dumb whining.
Imagine there are only Chevrolet and Honda (Apple and Android).
Imagine you could only go to Chevrolet-approved locations. That Italian place you like is on the destination list, but only because they pay 30% of their revenue to Chevy.
The movie theater is protesting the 30% fee, so your car physically can't even visit. It's prohibited.
The new boutique really wants to get business. After all it bought land and paid for real estate in a prime location. But Chevy doesn't like the look of it and asks them to tear it down and rebuild.
All the artists at the market your Chevy brought you to are mad because they have to fork out to Chevy, and they're not even sure what Chevy has to do with any of this. They just want to sell their art.
The builders are complaining because everyone is driving these damn cars with their silly rules, and nobody used to work or think this way. But suddenly everyone thinks Chevy's demands are okay. They're not entitled.
And yeah, web apps, so you can go through the drive-through anywhere you want. That works fine for some places but it's not at all comparable to parking and properly visiting, for many reasons of capabilities and reliability.