On another hand when people buy computers low-performance/low-voltage cpus are very niche. You can use them to enjoy media in a similar way, yet people want I5s or I7s that sell great and contribute to most CPUs sold lately, so it's not that niche.
As much as mobile phone companies want to shorten the life span of their product to force you to replace your phone every year or so people still want their PCs to last as long as they can. The mobile phone market is different from the PC market, despite the fact that the performance difference is getting smaller and Intel wants you to replace your PC every year introducing minor differences between their motherboard sockets people still want the most performance, even if they don't need it.