It's really a lot more simple than you're making it out to be. The word 'purpose' refers to intent, not capability. Xbox is a gaming console because that's what it was meant to be. The iPhone is intended to run many different categories of applications, because that's what it was designed to do.
In that case, why is the EU forcing Apple to support alternative app stores for watchOS and tvOS, not just iOS and iPadOS? The Apple Watch and Apple TV aren't designed to be general purpose.
Because they don't have the numbers to matter, that's why. I know it can be hard to keep several distinct conditions in the head at once, but it's important to remember that just because one can satisfy a single condition does not mean a law which requires several conditions to be true will necessarily apply.
I think you misread my comment. The EU is forcing Apple to support alternative app stores for watchOS and tvOS. These are not general purpose devices and they have comparable or lower sales than game consoles.
Because they're interconnected enough that the EU lumps them in with the rest of the ecosystem for anticompetitive purposes? I wasn't necessarily agreeing with the rationale above, just commenting on what a 'special purpose computer' is.
