that may be true.
but as I've said before, these devices are already becoming more PC like.
and even if the upgrade components are proprietary, that would still be a lot more convenient than having to buy a brand new $400-$500 console every year or so.
the new consoles can be designed as such that all you have to do is open a slot on the back or underneath the console, remove the existing component ( memory, gpu, etc. ) and put in the upgrade unit.
And these upgrade units ( even if proprietary ) cost about $80-$100 each. something like that.
so, as games in the mid or late cycle require more power ( for example, the box could say "requires at least 10 GB of RAM" ), you'd have to go out and buy the upgrade unit for around $80-$100, and then open up the slot in the console, remove the old unit, and put in the new unit.
it could be designed to be simple and straightforward enough for non tech users, which is the appeal of a console.
and spending $80-$100 on upgrade units every few years or so to essentially extend the life of the console is a heck of a lot better than having to spend $400-$500 to upgrade to a new console.