This is market economics 101. If AMD were to disappear, Nvidia would be able to crank up their prices, up to the point where GPUs become so expensive and lucrative that another competitor(s) would decide to enter the market with their own GPUs.
Most of you younger people have only known AMD and Nvidia. But the field used to be filled with lots of competitors - 3dfx, Matrox, SiS, Tseng labs, S3, etc. The jump from 2D to 3D graphics card significantly raised the required competency level to remain competitive, resulting in a lot of culling and consolidation. I had one of Nvidia's first GPUs in my work computer (back when they were nVidia, and 3dfx dominated). It sucked - not just slow but buggy (hardware bugs). I never would've predicted they would go on to become the dominant GPU designer. If I had had money at the time, I probably would've shorted their stock (and be homeless today) - that's how bad their product was. So you never know what the future will bring - David regularly slays Goliath.
Phillip Corcoran :
Intel processors aren't overpriced - - they are simply superior to the competition (mainly AMD).
More precisely, Intel processors are priced high enough that people are still willing to buy them, but low enough that they (1) don't give AMD enough room to price AMD CPUs higher so they can invest more money into R&D and catch up to Intel, and (2) don't encourage another competitor to enter the CPU market because the prices are so high.
Right now I'd say ARM (a RISC architecture) is Intel's biggest threat. Not because ARM CPUs perform great, but because CPUs are getting so fast that 99% of people's computing tasks can be accomplished with a low-end CPU like ARM. So Intel's speed advantage doesn't matter as much anymore. The new metric (for general sales, not enthusiast sales) is performance per Watt, or $ per performance per Watt. The 2.3 GHz quad core ARM7 in my phone costs about $25 and blows away the $200+ PC CPUs I had in the 1990s and some I had in the 2000s.