As a personal preference sure. But then he's free to look for a company where he can keep using Clearcase instead of sabotaging the change and holding back deve

As a personal preference sure. But then he's free to look for a company where he can keep using Clearcase instead of sabotaging the change and holding back development for everyone, just to avoid having to learn git even though the company is paying him to learn it. Clearcase does cost licensing money for the company though and also time in onboarding new grads who are already familiar with git. Git is also supported out of the box by all the CI/CD and modern dev tooling. Getting tools to work with Clearcase is a wasteful effort. So I can't see how his point would be valid in any business sense other than stubbornness.