The fact that frequencies stopped going up was the breakdown of Dennard Scaling[1], not a breakdown of Moore's Law[2]. We're still finding ways to pack transistors closer together and make them use less power even if frequency scaling has stalled.

[1]https://en.wikipedia.org/wiki/Dennard_scaling

[2] Though Dennard's paper came out in 1974 and the term "Moore's Law" was coined in 1975 so they've always been a bit confused.