Both pessimistic and incorrect.

You can observe the vast number of libraries across all ecosystems that are in use, as reliable libraries, well into functional obsolescence. Not to say some niche software doesn't suffer the fate of "nothing new, so it's dead" but that's not the norm.

Web frameworks are never feature-complete, per se. There are always new technologies and workflows to support. Frameworks are usually considered dead when the development halts in exhaustion or in transition to another project (as individuals, the development team members drift to these modalities), not when they are "done" by some finite collection of features.