So titles like Assassin’s Creed have already been available on PlayStation Now and could be played on any budget portable PC.
AC up to Syndicate, CoD up to Black Ops III, Far Cry 5, etc are on GeForce Now.
PlayStation Now actually works as much as we would expect from MS’s service (will be interesting to see what MS does about Sony’s patents in this area as they absorbed all those OnLive patents and Gaikai - there may already be some cross-licensing deal in place or it may be a non-issue today) and I’m yet to see anything that makes it sound like MS will have any different experience with 3rd parties than Sony already does (in terms of which games get offered on the service). The only real differentiator MS have is their 1st party games, same as on the consoles.
Edit: The number of current players who have offered a mobile and desktop solution and found the desktop one to be the focus of their ongoing business actually makes me think the mobile focus here is going to be something MS pivot away from. Only because that’s how it’s gone for several of the earlier movers in the market who also though the demand would be portables but actually (as wireless isn’t great for latency & this kinda makes a lot of sense for business person on a laptop in their hotel or streaming to a second TV without needing to own a second console or drag them around the house etc) found most consumers used it on lower power devices you don’t hold.