I, on the other hand, have a lot more sympathy for Apple: Many highly successful people and many businesses have never owned any of there products. They are not a monopoly. Why can't market forces just regulate them ??
However, they become undesirable when they are abused to undermine cometition in other markets. For example: Apple has successfully prevented competition to Apple Pay for a long time, by only allowing their own products access to NFC. This meant that parties that were already specialized in handling payments, had no chance to compete, despite them being in an excellent position to do so.
If this behaviour is left unchecked, over time we will end up with one single company dominating most markets. I feel that's undesirable. Given the number of dystopian novels on that premise, most of society considers that future to be undesirable.
Preventing that future is a major part of DMA.
As a user, I was quite happy with my personal Android phone while developing for iOS, both for hardware and software, because absolutely nothing is requiring consumers to buy Apple in the first place as basically every App you care about is shipped to both platforms anyway.