Two things I can think of: for consumers, applications don't currently make the best use of multiple cores. There just isn't enough work to do on them. For gaming at least, DirectX 12 will remove a limitation that only one CPU core can control the GPU at a time. That may push demand for more cores upwards over time.
Second is that cache coherence gets really ugly the more cores you have with a single shared memory. From what I understand, this is a limitation of assumptions in the x86 architecture. A completely new architecture might sidestep the problem, and indeed I've heard of 1024 core machines etc, which I doubt have just brute-forced cache coherence.
Second is that cache coherence gets really ugly the more cores you have with a single shared memory. From what I understand, this is a limitation of assumptions in the x86 architecture. A completely new architecture might sidestep the problem, and indeed I've heard of 1024 core machines etc, which I doubt have just brute-forced cache coherence.