Steam Home Streaming works pretty well on a LAN. Quality-wise, with my desktop at home its even higher quality than Xbox Cloud Gaming. I've got many hundreds of hours on my Steam Link. I just wished they'd make it work well outside of the LAN. I've had mixed experiences trying to run it on a few different VPN stacks. I ran into challenges of it not seeing the other computers, the stream being very unstable and crashing, and other issues. Plus, it means I need my computer's local console unlocked at home, but I prefer my computers to get locked automatically. And even then I've had games get in some stuck state launching or closing where I had to manually intervene on the local console to fix it.
Meanwhile, with cloud gaming I just click launch and the game is going. There's no waiting for updates. There's no managing a local console. I don't even need a gaming rig.
Also, you mention "Most of the United States in particular", I am in the United States. This has been my experience in one of the larger metro areas in the US (DFW). I don't get why it would be viable here but nowhere else in the US. 43% of US households have fiber-optic home internet. 60% of households live in areas with 5G coverage. I haven't been on many trips since getting it, but even a few years ago I could manage to sometimes make Steam Home Streaming work from a hotel WiFi on VPN at various places around the country, even with its challenges I mentioned above. I've got family who game a good bit with PlayStation cloud gaming service on a 5G home internet connection.
43% fiber and 60% 5G definitely isn't 100%, I agree. But it does mean there's a pretty big chunk of consumers who can use this, today. I'm not in some magical internet wonderland inhabited by just my family and me. 43% of ~330 million people is >140M people with home fiber internet, nearly 200M people with 5G coverage, today. And that's just ignoring all the consumers with actually decent cable internet connectivity.