> So a lesson in Software development is similar to betamax and VHS, so marketing is still a winner over technically superior architecture and ease of use.

this is an amazing opinion. Git won over mercurial because its capabilities and usage model are vastly better than that of mercurial. I had all of my projects on mercurial for many years and finally switched over to git, it was like a whole new world opened up. My daily workflows are now entirely based on concepts that are complete anathema to mercurial, where changesets are just objects that can be moved around or deleted once no longer needed, where commits to master represent complete features in a single changeset. Throwaway or hypotehtical branches are now changesets in Gerrit, rather than "feature branches" that exist forever whether or not they were used. I'm not sure if mercurial found a way to work out those problems of having zillions of little "fix typo" style commits crowding up a feature as well as zillions of dead feature branches forever crowding up the repo, but it at least was not apparent to me seven or eight years ago which would mean it's not easy to use.