Your time horizon just isn't long enough. I've been working with computers since the time of the S-100 bus systems.
What you're talking about, and what most people talk about regarding GPUs today, are all just and evolution of existing tech. You note a trend (moving to iGPUs) but don't see the ultimate conclusion of that trend.
Higher resolution, faster 3D rendering, etc isn't going to stop the current trends. And the current trend is that dGPU markets are shrinking - and that pace of shrinking is accelerating. It's partly because the desktop space is stagnant, but within that space dGPUs are losing ground to iGPUs as well.
If dGPUs are to regain any kind of traction in the market it will have to
be from something revolutionary that you can't effectively do with a SoC or iGPUs, it's not going to come by doing the same thing.
Companies like Nvidia, Google, Intel, and Microsoft understand this. Technologies like Hololens, Oculus Rift, Google Glass, and Meta Lens are all efforts to move to the next generation of UI's.
If we are still on the LCD / mouse paradigm in 10 years, it will be almost entirely on iGPUs.
If there is a long term future for dGPUs and the graphics industry in general, it will be doing something like this :