> That definitely includes mercurial etc.

People tried mercurial. They went back to git.

I tried Sapling (Facebook's fork of mercurial with more polished git-compatibility layers) and never looked back for any of my own projects.

I recently started a new job where the vanilla git CLI is the only git frontend installed on company servers, and the regressions in user-experience are painful :(

Some did, sure. I made a more limited claim: you can convert back and forth between mercurial and git.