> Moore's law (as it is generally talked about) is actually a pretty good indication of how much computational power we can get from a single processor core.

Imagine that we have the technology in place to manufacture silicon chips at 2nm. How would we design CPU cores with a substantially better single-thread performance, when clock speed is limited? Optimization techniques like OoO execution and register renaming have already been pushed to their extremes. Increasing caches beyond a certain point has been shown to deliver diminishing returns.

We just don't know fundamentally how to design a substantially faster CPU core.