Not quite double, I waited for a ~$700 deal, but yeah, you pay a premium for the form factor. If you aren't looking to optimize both performance and small form factor, $500 is reasonable. Less if you can recycle an old case, psu, etc.
Yeah, if you're smart about these things and know where to look and don't mind some diy, an adequate desktop can be found for $200. A game streaming service would be perfect for that sort of setup. But I still think the price point for streaming is wrong for mass adoption, and for anyone with even minor gaming interests already (e.g. you've bought a decent amount of games over the years) then being able to use your existing library of games is an essential feature.
Wrong subthread, small apartment isn't regular travel ;)
But I don't think there's need to argue this further, I think the point that there isn't a one-size-fits-all solution has been made exhaustively, by everyone.