Seems more like it's targeted at the PC market for people that want a living room system and already have a steam library.

I thought that was obvious? That's definitely how they've presented it, it's also how the steamdeck was presented. I mean the whole thing of the steamdeck was like "do you have a giant backlog of stuff you don't play because the big noisy lightbox is inconvenient and isolating?"

Sony alone is so deeply entrenched in Japan it may as well be a branch of the government. PC gaming is increasingly expensive and fringe with mobile gaming being the largest and most profitable area. The steam cube thing seems pretty clearly positioned as "Just plug it in and turn it on, congrats all your games now work with a controller on the couch" box.