Buildout came first and can do more things than pip can. If your workflow was heavily dependent on buildout, I could see how someone would see pip as inadequate

Buildout came first and can do more things than pip can. If your workflow was heavily dependent on buildout, I could see how someone would see pip as inadequate. Buildout also came from the Zope community, so that will immediately break people up into camps. My impression is also that more people use pip now particularly with its integration with virtualenv. I can't imagine not developing with pip and virtualenv now.