For what it's worth, we use git in my workplace. Everyone is quite happy with it. Of course, no single person is really going to be able to tell you how common it is.
I suspect the continued prevalence of cvs/svn is much more to do with inertia than anything else. They were definitely among the best (if not the best) choices for a long time**, and a large number of developers have had the chance to learn to use them well. If most of your workforce is already comfortable with them, and they're good enough, how many companies can we really expect to try something new?
Another common factor in corporations' decisions has to do with a sort of stigma attached to free software. People tend to associate monetary cost and value, perceiving more expensive products as better (For example, I've read about a psychology study where people were given the same wine twice, and told one was a more expensive variety. They tended to rate it as tasting better). With software, there is a certain amount truth to this attitude - you can often buy some guarantee of support and maintenance with a product. We all know established open-source projects can easily still win out (more testers, more documentation writers, faster bugfix releases...), but I'm sure this still motivates many companies to purchase VCS/SCM products. However, this is clearly not the reason people are using cvs/svn.
** Please, no flamewars! I'm a diehard git fan, but I know it hasn't always existed. Of course, some still disagree, like Linus Torvalds:
For the first 10 years of kernel maintenance, we literally used tarballs and patches, which is a much superior source control management system than CVS ... The slogan of Subversion for a while was "CVS done right", or something like that, and if you start with that kind of slogan, there's nowhere you can go. There is no way to do CVS right.