> I occasionally ask our principle / sr. Python engineers about this, and their response is always, "These things come and go, virtualenv/wrappers + pip + requirements.txt works fine - no need to look at anything else."

At the macro level, this seems like a bit of a self-fulfilling prophecy: if all the senior and principal engineers using Python don't care to take a look at something else, then it's not too surprising that new solutions don't end up sticking around. That isn't too say that there does necessarily need to be a change in the Python community's choice of package manager, but the rationale for not even considering looking at other options doesn't seem super compelling.