The code itself stays static unless someone edits it — and those edits only matter if the fork becomes dominant.
If the code remains static unless developers edit it, then how can the system be self-improving?
If we are talking about Darwinian "survival of the fittest" for forks, then yeah, Bitcoin and many altcoins fit that description. But that doesnt mean they are "self-improving systems." There is no magical self-improvement happening beyond human developers building, and users choosing.