The PlayStation 3 has 256 MB of RAM, not exactly on par with a current PC gaming system, which can easily have 16 GB.
I would argue that the rising production costs to produce games that actually make use of ultra-advanced hardware are more to blame for the slowing of the graphics race.
You can always do things faster by doing things in parallel. It just gets much harder to program them.
Gaming PCs also have a general purpose OS on them. It's not an apples-to-apples comparison. One is a general purpose computer, the other is a device designed for a single purpose.
But that's beside the point: the games industry drives the graphics card business, but that is only a one part of the consumer computer business. General purpose processors are a larger part, and processor performance improvement is not the exponential curve it was a decade ago.
I would argue that the rising production costs to produce games that actually make use of ultra-advanced hardware are more to blame for the slowing of the graphics race.
You can always do things faster by doing things in parallel. It just gets much harder to program them.