ESR's post provides a link to a long but worthwhile article by Jelmer Vernooij on the history of Bazaar and why it lost to Git.
The key paragraph:
We lost sight of what mattered for our users, focusing on features that were nice but perhaps not as necessary as we thought. We overengineered. We didn't get rid of the crufty unnecessary features. It's harder to comprehend, contribute to or fix performance issues in a large layered codebase. And the larger a codebase becomes, the larger the surface for bugs, the harder it is to refactor.
https://www.stationary-traveller.eu/pages/bzr-a-retrospectiv...