the target audience is people who don't want to pay for expensive PC rigs/consoles and want the flexibility of playing AAA games on their phones or low powered laptops anywhere there is a good connection.
Problem is the number of Android phones that can do that is small and not everyone has good connectivity to play. Also you often pay full or nearly full price for games while also paying a subscription. On top of that most games haven't been optimized for streaming and don't play at the promised 4k.
Honestly streaming games is going to happen. Many of the big boys are investing heavily on it and the potential is huge. The end device and network just need to handle the video bandwidth and latency. You can scale the servers to handle better games. And if you have been following the progress of Elon Musk's Starlink and the promise of low latency global satellite internet, it's only a matter of time until we could stream powerful games anywhere.
But, like you I imagine, I would still keep upgrading my PC to handle the next generation on top of the reasons you listed. Mostly because I can (somewhat) justify this due to work requirements but also because I like having my game on my computer and not at the mercy of some corporate entity with a reputation of giving up on projects