Maybe Apple's goal is to become irrelevant enough to not be subjected to the DMA. I mean, making developers despise you is a brilliant first step towards such an end!
Why is size a question here? If apple is subject now, but then dropped to 1/10th the number of users, could they suddenly no longer be required to adhere to the DMA? Why is the size of the provider suddenly a test to determine if consumer protections are in order?
The DMA, digital markets act, is about fair competition, not consumer protection. If you got 5 users, you do not have the necessary leverage to matter.