[ahartmetz]

In addition to software not being ready:

It detoured into a company having no need to improve its products too much because they were already the best. If the technology is somewhat stagnating, it is best not to release all the improvements at once. After core counts have increased, what else will still make people buy new CPUs? Maybe I lack some imagination here - and so do companies making phone CPUs, which can't think of anything better than upping the core count.

Also, high core count CPUs are slightly more similar to GPUs, and Intel seems to be trying to keep the GPU threat at bay. There is no reason to believe that Intel couldn't design a competitive high end GPU, but that is not where its entrenched advantage is. (This part is not my own analysis, I read it somewhere else and consider it highly plausible.)