I don't think you can necessarily draw conclusions about Intel vs TSMC from Intel vs AMD.

Yes, building top-of-the-line CPUs is hard and it's impressive that we saw the dominance flip in the course of just a few years.

But I think frontier chip fabrication is a bigger juggernaut than "mere" CPU design.

(Your conclusion could still be correct, but I don't know if I buy the high-level reasoning).