That said, the same argument could be made for mobile phones as well, so it's clearly spurious.
These kinds of arguments are hollow. Especially in gaming, if you make a good console with good games, people will want to hang on to them and play them for literally decades. But even ignoring that specific aspect of gaming culture, it really should not be up to some top-down, self-serving analysis about what most consumers should expect. Otherwise it's just a race to making the least consumer-friendly product so you can make legal/political arguments about consumers obviously want to buy expensive garbage which they expect to break beyond repair in a few years at best.
The value difference between 10 year old console (PS4!) and new one, can be smaller than 10 year old LCD vs new OLED.
I disagree with your point, but I'll reply to this one:
> That argument made sense 10 years ago, but since then we've seen a lot of slowdown in computers, consoles and mobile phone progress
That argument doesn't made even less sense 10 years ago in my opinion. When things are moving fastest (eg, most profitable) is when parts must be made available for consumers to repair themselves. When things are moving slower, then the IP/schematics should absolutely be provided if nobody is willing to make the parts.