Sun is not a great compare because it didn't have the type of network the author lays out. There was a relatively small market in Sun-only software, for example, and a smaller set of people who exclusively programmed for Sun hardware.
If I were forced to use Sun as a comparator, I would say their supremacy in the general-purpose high-end Unix workstation niche was never toppled, but that niche declined to irrelevance in popularity. The takeaway from that analogy here would be Nvidia is in trouble if people stop using GPUs in AI applications.
That's fair. It seems we all agree that the timeline here is much longer than some might understand from the author's remarks. But ultimately I agree with the author regarding Nvidia's competition — it's like a dog walking on its hind legs: it's not done well; the surprise is that it's done at all.
Sun Microsystems did great through the 1990s. But by the time the LAMP stack was fully mature, web servers had been commoditized.