That is not my experience. Until recently, I used to pin versions in requirements.txt, then from time to time I removed the pinned versions, reinstalled everything, tested and added new versions to requirements.txt. Most of the work was testing for incompatibilities, but no package manager will help you there.
Recently I switched to pipenv because zappa insists on having virtualenv (as app dev I never had any need for it - but it seems my case is an exception, as I almost never work on multiple apps in parallel). Pipenv does make version management a bit easier, but it wasn't difficult (for me) to begin with.
From talking with other developers I know my view is somewhat unorthodox, but I haven't encountered the problems they describe, or the pain hasn't been that big for me to embrace all the issues that come with virtualenvs.
