The knowledge bottleneck is in the human population, which is then reflected in Stack Overflow and blogs, which is then reflected in LLM's.
LLM's aren't doing anything special to stifle new tech adoption. New tech is harder to adopt because it's new tech, because people in general are less familiar with it.
(And there's a little bit of a training delay in LLM's updating, but that's a minor aspect here compared to the years it takes for a new Python package to become popular, for example.)