> I always tell these people to just sign up for a password manager and they always resist and say no. I must be missing something obvious.

Maybe they don't want to be relying on a random third-party for all their passwords?

Rather than getting them to sign up for a password manager, what about getting them to install a password manager? I use https://www.passwordstore.org/ - it encrypts your passwords with GPG, and shares the storage via a Git repository for synchronisation between different machines.