DOS/Windows and PC clones were by no means the best available, but they were cheap, ubiquitous, and versatile compared to alternatives that were either much better at one task but more expensive or better at everything but wildly expensive. They were "good enough" and represented a solid improvement over what many existing computer users had as well as a good entry point for new users. As such they spread like wildfire and became the standard while the expensive alternatives either became hardcore niche or vanished.
Though to be fair it was Linux more than Windows that killed them. Dos and Windows were competition for DEC and - ironically - IBM.
My work is showing promising results (if you can get past the way the AI tries to describe what I am doing). https://sw-ml-study.github.io/emufpga/index.html
I am doing this work initially on a 6-Xeon-cores Linux workstation with an RTX5060-16G to run MoE models larger than that. Then I will be moving this to a server with a lot more cores (Dual 32-cores) and a mix of SAS HD and SSD drives, using older GPUs.
Ultimately, I hope to build some FPGA/MCU "accelerators" that process the expert weights on systems with not enough CPU cores to offload the experts. If I can enable large capable models to run on older hardware, keeping the limited GPU VRAM for context and things that must be in VRAM, I can get useful work out of my old refurbished systems without paying today's RAM and VRAM/GPU prices.