Maybe you live somewhere with crazy-stable, ultra-low-latency internet covering every little nook and cranny you could ever care to find yourself in, but I doubt this is the case for most of the world. Until we realize this utopia globally a remote desktop setup is simply not flexible enough.
I am of the same mind. Desktop for heavy lifting and a mid-range Chromebook (technically a chrultrabook now) for browsing w/ a lightweight yet modern feel.
I do think the plunge to leveraging a desktop/server across devices does require an understanding of ssh/rdp and tailscale/reverse proxies though, which is why it isn't as popular as it could be.
One could argue, that the "reusability" of the laptopbricks, in a desktop-server blade like structure is the biggest argument for the framework as a laptop though.
Using Steam Streaming/Moonlight-Sunlight/Tailscale is a dream for remote gaming.
You are absolutely right- forgive me, im kind of out of touch with the whole steam revolutionizing gaming on linux.
I think the comment about the "transporttax" on hardware, ergonomic and cooling still holds up though even in a world where things like steam-deck exist.
Even more so, if you may have lightweight ar-headsets one day, with a glorified cellphone + mouse and keyboard.
One of my mentors had the great sentence: "I dont buy laptops- they suck, because they are tailored to transport. I buy desktops- and connect them via internet to flat transportable terminals. And desktops can be upgraded, merged, reused and send to the closet as server at the EOL-"
And he was kind of right. For almost all purposes, even for gaming in a way- a remote desktop is kind of superior. Yes, stadia is dead- but for everything else- this shall do.