Your mobile device is a gateway to much of the world. You seem to think it would be okay for a car manufacture to make it impossible to use your car except to drive to business that pay the car maker 30% of every purchase. I'm guessing you'll say people should be able to opt into such a car if they want but if that car has 60% of the market now it's effectively influencing the entire economy. Prices of groceries are 30% higher. Prices of clothing are 30% higher. Any company who wants people to come to their store are forced to sign up to pay the car company 30% or else they won't have access to 60% of the population.
Can you see the issue now? It doesn't matter that people could by other cars. It matters that Apple's market is so large that its influence is too big to be left as is.
The question is, can you buy a car from a different manufacturer? When it comes to cars, yes you can.
Is apple a monopoly? Probably not, because you can also switch to android.
Does Apple have a large enough share of the market to influence the market? Likely, which is why the EU has DSA and DMA now.
No, the question is "does one company have too much influence over the digital economy". The answer is yes. Apple has influence over 60% of the population. They extract 30% from all digital transactions. If you want to sell digital content to iPhone user's you're required to give Apple 30%. That's too much influence for one company.
> The question is, can you buy a car from a different manufacturer? When it comes to cars, yes you can.
You can, but why would you if you have no idea that your Apple purchase comes with all of these negative consequences?
I would guess that most Apple users don't know the implications of their purchase, and therefore they have no real incentive to look outside of Apple. Garland even addressed this in his speech: Apple disincentivizes you from choosing non-Apple products. They make it look like their products are better, but really it's the opposite: they make their competitors look worse due to their own purposefully terrible interoperability.
Contrast that to an Apple Car that only lets you drive to Apple Grocery stores with a 30% toll: the user is going to see how bad that is and naturally they'll find better alternatives on their own.
Poor analogy. This is already an issue with servicing automobiles. Overly-complicated construction and proprietary tools that can only be acquired by licensed dealerships. Read: Audi, Mercedes-Benz.
Can you see the issue now? It doesn't matter that people could by other cars. It matters that Apple's market is so large that its influence is too big to be left as is.