It depends. It's more about developers pigeonholing themselves. Some CVs come along and are e.g. all Java, EJB, Spring, Hibernate etc. - they present themselves as completely unidimensional and more or less rule themselves out of something broader.

There are different things you learn when you've coded in a mix of C/C++, Java/C#, Ruby/Python, and perhaps something functional. But having all your experience in one of these buckets is more a sign of a junior developer, or the old "one year's experience ten times".