This is one of those assertions that is simultaneously true and irrelevant. A developer who is comfortable in git is better than a developer who's only willing to use Clearcase. How they get to be one or the other doesn't play into the value calculation. "That's not fair" is one of the least compelling arguments in business.

But then, I strongly object to the notion that older developers are likely to push back on (say) git. More likely, given the developers over 40 that I have known, is that the developer is likely to think that choice of VCS is banal; older developers are less likely to fetishize git or hg, which is a productivity trap for developers who are passionate about their VCS.