We may discover the stagnant generation-to-generation performance uplift over the past ~10 years was mostly due to lack of competition in the market.
The stuff I've read about the new process nodes from the last decade indicate that moving to those hasn't been easy. And the chip designers haven't had it easy either, with each new process comes a longer and longer list of restrictions and other difficulties.
Transitioning an existing CPU design (for example) to a new process node was never easy per se, but it has never been harder than it is these days. That's part of the slowdown.
And that's great. But that'll also be a one-time thing in a sense. After it has moved to the latest process node, it will be on the same trajectory as other architectures.