Perhaps what we need are reliable tools that will robustly port commits forward from old VCSs to new ones. Does something like that exist? The most common defense of this code seems to stem from a vague sense that VCS history is more ephemeral than committed code. With proper tooling (or better awareness of the appropriate tools if they do in fact exist), this anxiety could potentially be allayed.
Eric S. Raymond wrote a tool called reposurgeon[0] for just this purpose. Coincidentally, he used it to migrate Emacs to Git and clean up the repo, although I'm not sure how much manual work he had to do to besides running reposurgeon.
