I think this is true for essential complexity. And indeed it's one of the best reasons to release early and often, because usage helps clarify which parts of the requirements are truly required.

But plenty of projects add quite a lot of incidental complexity, especially with technology choices. E.g., Resume Driven Development encourages picking impressive or novel tools, when something much simpler would do.

Another big source of unneeded complexity is code for possibilities that never come to fruition, or that are essentially historical. Sometimes that about requirements, but often it's about addressing engineer anxiety.