This is also how OS, app distributors and platforms will ensure that they get their 30%+ cut of all revenue generated using their products, as well.
Similarly, this is how OS providers will ensure that apps built for their platforms can't run on other operating systems. You already can't run SafetyNet-enabled Android apps on other platforms despite Android support existing on Android and Linux.
They just made it illegal to forbid sideloading for example. On its face it’s going to be illegal for Apple/Android to use attestation to lock down their devices further, indeed they are now legally required to open up in the EU.
Maybe they would go in one direction in the US and the opposite outside? Seems unlikely to me though…