In a project with about 10 prod deps, pipenv install took about 10 minutes. Then we added jupyter, scikit-learn, andtensorflow and it ground to a halt. Over an hour later, it was still "locking". pipenv lock --clear didn't help.
We switched to pip and it installed all the deps in a couple of minutes. We reckon pipenv needs to be at-least as fast as pip in all operations, as dev time is valuable. We can all agree an hour waiting for an operation is not justifiable, especially for a tool as handy as pipenv.