People say this about AMD/Nvidia, and Intel/AMD, and it has, and always will be complete and utter nonsense.
How few people can think logically.
I had a Q6600, lets assume AMD didn't exist and Intel didn't move anything forwards at all, then the 2500k I have now, wouldn't be anywhere near as advanced as it is and cost the same as the Q6600, or the 2500k with no competition would cost £600..... in either situation I wouldn't buy it. Thats it, the whole argument, if there is no progressoin and there is zero value, no one would buy.
Intel have ONLY been competing against Intel in cpu's for the past 5-6 years, AMD's competition hasn't had any effect on Intel, AMD have been seriously better value for huge portions of the customer base for donkeys years and its made no difference.
GPU's are a better example, I had a 4870, if the 5870 either cost twice as much, or the 5870 was only 20% faster for the same price... who would buy it?
I bought a 5870 because it was 70% faster and good value, I bought a 7970 because it was 70-80% faster, and it was good value(I got one at £305 maybe 2 months after launch). Assume there is no Nvidia, if you have a 7970 and a 9970 that is either £600, or 20% faster and £400, what percentage of people on this forum would pay the £600 or £400 for something barely any better? More importantly, how many people would buy at 9970 if it was 70% faster at £400, and how many of them wouldn't if it was only 20% faster.
AMD, Intel and Nvidia need to compete with THEIR OWN products otherwise everyone would buy one pc, one gpu, and then barely ever bother again.
Is it better to sell 20million 7xxx series cards, then 20million 9xxx series cards, or 20mil 7xxx, then 200k 9xxx series cards, then 5 years later those 20mil 7xxx buyers all finally see a worthwhile upgrade. 20mil sales a year, or 20mil sales every 5 years.
Intel, AMD and Nvidia HAVE always been competing against their own products, they always will, and the competition has little to no effect on what they do.
If all GPU's shot up 100% in price due to no competition, 90% of sales would evapourate.... if they stopped providing performance increases, people wouldn't need to upgrade, or new computers, etc, etc.