Updating a lockfile can be very slow. A standardpipenv lock easily takes well over a minute for me:

$ time pipenv lock Locking [dev-packages] dependencies…Locking [packages] dependencies…Updated Pipfile.lock (abef76)!real1m56.988suser0m21.805ssys0m2.417s

This means every time I need to install, uninstall or upgrade a package I need to take a 2-minute break to wait for pipenv to finish updating its lockfile. I'm not sure why that is; yarn and npm seem to perform a similar task but only take seconds, even for projects that have many many more dependencies.