I'd be interested in a bare bones version. That way I could shop for RAM and an SSD myself.
Maybe someone can invent a universal system to allow CPU and GPU upgrades on a desktop computer.
I hope a repairable and upgradable Steam Machine would help more people dip their toes into it.
Valve also could have gone the Framework route of releasing a motherboard+CPU combo so you can upgrade later down the line just by swapping the board out.
I guess they can earn more money by soldering everything on the board and having you buy a completely new PC every time you want to upgrade.
Its obviously less reliable, but with read only OS with only occasional writes it will work just fine for decade.