That's simply untrue. Bzr was dog slow on repos with lots of history. It had lots of early users and support from hosting services like Launchpad, Savannah, and SourceForge. I'm certain that everyone didn't migrate to git because of hype. I mean, it's not credible to say the Emacs team stopped using it because it wasn't fashionable.
There were lots of DVCS projects at the time, like arch, darcs, and dcvs. People were running all kinds of experiments to explore the Cambrian explosion of new ideas. Some of them did some things better than git, but git handled most of those things reasonably well and it was fast. We all mostly ended up on git because it was generally the better option. It earned the hype, but the hype followed the adoption, not vice versa.