Well, AMD developed x86-64 technology did they not? Intel was left in the dust with that too originally.
But it's good in the long run. These companies keep pushing themselves to advance technology and it's the consumer that has benefited.
The reason nVIDIA needs to use a more expensive 512-bit memory bus is because they don't have the capability to advance GDDR memory the way ATi can. Still using GDDR3 because they don't know how to develop anything better.
The difference is that JEDEC is suposed to be an "open" group to set standards in the industry. If they make one company's development to be an standard that's not fair. It's not a matter of "I can or I can not". It's a matter of "what's the price I have to pay?" I'm 99'9% sure
any chipmaker can implement anything like that. Maybe not as well, but they can...
EDIT2: I have made my brother read this and he has said I didn't made my point clear about the above. Here's further explanation. It's not that I don't like a company to own the rights over something they have developed. It's the fact that suposedly Ati has set standards for the industry for something they don't manufacture, memory chips. They are the customers not the developers and IMO shouldn't be the ones setting standards, as those may not fit other customer's needs. The fact that it's always Ati who sets the GDDR standards and that I know how the world works, and that's 99% politics, my view is that JEDEC aproves Ati's designs because they are "used" to them. That's not good for the industry nor the customer IMHO.
EDIT: Just as a showing of how they can. I studied Telecommunications Engineering. I left in the second course because it was a lot about programming software than what I liked and first thought it would be. But in the meantime and without a lot of studying in that matter (I mean I left in the second course) , I learnt by myself how to do a SDRAM memory controler with the help of Altera programable FPGAs, for a project in which I needed more memory than the one that I could fit in the FPGA they gave us. Was it fast? No mama, but it worked, and it was me. Come on...
Plus Amd developed x86-64 because they have a joint development agreement with Intel. Any improvement made by one part can be "copied" without a patent infringement (more or less that's it).
This is not the case with Ati - Nvidia AFAIK. Plus JEDEC dictates what the manufacturers are going to do. If JEDEC says GDDR5, it's GDDR5. Let's say Nvidia comes up with a new own memory design, they have first need to be aproved by JEDEC. If the new design is similar to GDDR they won't get aproved. The case is that GDDR5 is the standard and if Nvidia wants to use it, probably has to pay to Ati because they probably have the patents over it. Any try to make something similar will fail into patent infringement.
Following the example of x86. Do you really think that nobody in the world can make their own x86 processor? Nvidia for example to follow with the same players. Of course they can, but patents prevent them from doing it. You would be surprised how patents can prevent many companies from doing lots of things in this industry. The computer industry is not that much about innovation really, it's more the sort of like for double the performance double the lines or the clocks, etc. There are some things you can innovate, but offen times they are easy to think off and obvious, but at the same time are not worth at that time, so you don't implement them ar even care about them. So you forget about them, then a month later you think again and say "Ey in the next year this could be handy". You go to the patent's office just to find out you are 3 days late and someone else has "taken the lead"... That's how this things work. The worst thing, besides this or in adition to this, is that there are plenty of "companies" out there which their only job is finding those "holes" and making patents of them even though the won't even develop them into reality and never have thought of doing it. It sucks.