Perhaps you have to use your common sense to know there are only so many enthusiasts but there are many more gamers that cannot afford 1080-Ti. Enthusiasts consists of tiny fraction of the entire GPU and CPU market if you are insisting that the majority of sales fro NVIDIA or Intel comes from that segment of the market then I think you are wrong.
Just have a look at the 10-Ks. Nvidia's: "Gross margin for fiscal year 2019was 61.2%, compared with 59.9% a year earlier, which reflects our continued shift toward higher-value platforms". Datacentre is their biggest growth area today, and they have traditionally created specific high-margin products to extract value in areas with very limited competition.
The same thing is true for Intel when they don't have competition. They are the company they are today due to insane gross margin on Xeon and the explosive growth of cloud computing. DCG has been Intel's top performing BU for ages until recently. Expect the same story from AMD as it eats Intel's lunch in that market. High margin semiconductors are money making machines.