alt Hacker NewsThe way Git took over wasn't Git vs Mercurial (although that was a small part of it), but much more Git vs SVN, CVS, and people that never used source control before. It's similar to how Chrome became the dominant browser over Firefox. It was much more converts from Internet Explorer and Safari than advanced users that were already on Firefox.
That is an important point: in 2005 "all code must be in version control" was still a controversial idea, particularly for companies that made software but were not "tech" companies. A lot of git's expansion came from teams putting their software in a VCS for the first time.