I really wish people would stop talking about computer tech as "winning" and "losing". I mean, it's slightly better than "X is the new Y Killer from X Corp" bullshit we used to get, but its still ridiculous.
Mercurial, SVN, Darcs etc are all valid tools to use and all are maintained.
> you need to use it if you are in this field.
Wow, cargo culting much?
You should be familiar enough to use it when required, sure.
You don't need to use it if you're starting a new project. My client projects default to Mercurial, and I'll give them help getting up and running with hg if they aren't familiar already.
If you have developers who want to collaborate on your work, who are able to get git to do what they want, but who objecting to using something like Mercurial, you need to question their motives.
They're either not smart enough to actually use git, and instead just memorise commands without any clue what they're doing, OR they are objecting because we all know cool kids use git and they are a cool kid.