I've seen this happen over and over again well before LLMs, when teams are sufficiently "code focused" that they don't care much at all about their teammates. The kind that would throw a giant architectural changes over a weekend. You then get to either freeze a person for days, or end up with codebases nobody remembers, because the bigger architectural changes are secret.
With a good modern setup, everyone can be that "productive", and the only thing that keeps a project coherent is if the original design holds, therefore making rearchitecture a very rare event. It will also push us to have smaller teams in general, just because the idea of anyone managing a project with, say, 8 developers writing a codebase at full speed seems impossible, just like it was when we added enough high performance, talented people to a project. It's just harder to keep coherence.
You can see this risk mentioned in The Mythical Man Month already. The idea of "The Surgery Team", where in practice you only have a couple of people truly owning a codebase, and most of the work we used to hand juniors just being done via AI. It'd be quite funny if the way we have to change our team organization moves towards old recommendations.