The failure is primarily due to stagnation in single core speed improvements since 2003, compared to previous decades.

Yes we have more cores now, and single cores have got faster, but nothing like the scale of the 1990's when raw clock speeds increased 150x.

Moore's law is about the number of transistors, not the speed of the device. More cores are good, but software is hard to parallelize, despite decent efforts from the CS community.

There have also been efforts to put FPGAs into general purpose CPUs. These have also not taken off.

For most users, a single core CPU running at 30GHz would appear faster than 32 cores running at 2GHz.