I think there's an argument to be made that in practice, smartphones are typically used by most users as general purpose computing devices, while game consoles, despite being technically capable of being general purpose devices, are typically used for a specific purpose.

That being said, I would be perfectly happy if an outcome of this was that end users were able to install whatever software they liked on game consoles.

A smartphone has a pretty defined purpose: communication. It's powerful and generic enough to be a general purpose computing device, sure, but the vast majority of users use it to do just that: make calls, send messages (whether via traditional SMS or social media offerings). It has some secondary usage such as internet browsing (primarily consuming streamed content, these days) and photography (largely for messaging/social media purposes). Occasionally it might be used for something more heavy duty, like some light editing of photos and videos. Some people play games on it. But it's still oriented around being a communication device.

There isn't much difference between that and a modern gaming console (apart from the orientation being around games/interactive entertainment). Take my PS4, for example: beyond the games there's pretty capable light photo and video editing software, a web browser (based on Webkit, actually, and has a surprisingly pleasant and minimal UI/UX even when using just the controller and not an external keyboard and mouse), a ton of content apps (Netflix, Disney+, Spotify, YouTube, DAZN, etc) as well as Twitch and the Playstation Network platform (essentially social media). In my opinion the only thing holding it back from gaining more apps and completely eating up the lower end of the desktop market is that developing apps for it is prohibitively expensive (gotta order a dev kit). Even at that I still plan to keep it around as a very light desktop alternative when I replace it with the next generation.

Let's assume that phones are general purpose computing devices.

So what ? There is no legal requirement that computers must have user-installable apps or comply with some standard around openness. Nor is there some rationale as to why computers should be treated differently to any other device that can run apps.

And if Sony decides to ship a browser with PS5 does it suddenly switch to a general purpose computer device and must allow competing app stores. And if they remove it does it switch back to a console.

The whole concept is completely nonsensical and unworkable.

Separate the hardware from the software. The devices:phones or consoles, as hardware ARE general purpose computing capable.

The software limitations is where the arbitrary restrictions come in. But as you say there is no legal requirement for "user-installable apps".

But there ARE laws about anti-competitive behaviour. Whether they apply? The courts will decide soon I guess.

I can see it from the point where Apple makes Apps and yet also profits from their competitors Apps.

Mind you, I can also see a reasoning that by keeping an App in the market Apple can set a base minimum for quality, hence setting a floor for the experience for end users. But they could do that via their gatekeeping anyway too...

Any retail xbox one can turn on DEV mode and run self made UWP games and apps, switching back and forth is very easy.

https://docs.microsoft.com/en-us/windows/uwp/xbox-apps/devki...

That is what Apple should do then; allow people to install Android on their devices

Yes but for most people an Xbox or a PS4 is not a requirement for their livelihood.

Would you be okay with a Microsoft-owned app store that controls all app purchases and in-app purchases for all PCs?

That existed for years in the form of Windows RT. It's also an option in Windows 10 called S mode.[1] I wouldn't buy such a device for myself, but I'd certainly consider it for my grandmother. It seems like a useful way to prevent naive users from installing malware.

1. https://support.microsoft.com/en-us/help/4020089/windows-10-...