I can see why they'd like to push cloud gaming - if they have massive supercomputers on which the games run, they can throw system requirements out of the window and leave you only with demands for internet connection. Plus it'd assure everyone has an up-to-date game and probably inhibit piracy more than all the DRM methods. There would be two theoretical business models - a monthly subscription to access anything they have (I believe they have something like that with Origin Premium or w/e it's named) or free access with the old good buy-each-game.
As many people said, the first problem is access to high-speed internet. I live in walk distance between three major cities (300k, 50k, and 30k) that have optical network but I am still limited to the antenna on my roof and 10mbps. Yes, there will be a 5G network but even that has its limits.
And, the major issue: modding. Sims without mods? Nope, not taking part in that.
Then, we have more issues: UI customization (I know this doesn't apply directly to Sims but it does to many other types of games), vulnerability to DDoS attacks, potential lag issues for people living far from the servers, and probably more I forgot or just don't come to me right now.
