> Because maybe mercurial's real problems wouldn't show up until people started using it at scale.

I actually tried both git and mercurial almost a decade ago having had only experience with subversion, and found git to be much easier to understand and use. I don't recall what those pain points were, and am sure I couldn't describe them correctly if I did remember, but because of that I do expect such things to start popping up if more people used it.