A few reasons: - libs not available for Python 3 (this is a big problem for some people) - codebase work and don't need/want any evolution Python 3 provide -

A few reasons: - libs not available for Python 3 (this is a big problem for some people) - codebase work and don't need/want any evolution Python 3 provide - fear of Python 3 being unstable (that was legitimate during the first few Python 3 versions, not that much anymore) There are probably more.