I don't think that's correct as a blanket statement - you can use a passphrase, or remember a 14+ character password since you only have one to remember.
Even if it's only random-ish, password managers do key stretching (for example by hashing the password 600k times - bitwarden has a high default value and lets you increase it if you like) so that it has to take some computational effort to check if a single password is correct. That's why it take a few seconds to unlock your vault each time.
With these in place I think you're pretty safe for a long time. (Well, maybe until quantum computing breaks those cyphers?)
Even if it's only random-ish, password managers do key stretching (for example by hashing the password 600k times - bitwarden has a high default value and lets you increase it if you like) so that it has to take some computational effort to check if a single password is correct. That's why it take a few seconds to unlock your vault each time.
With these in place I think you're pretty safe for a long time. (Well, maybe until quantum computing breaks those cyphers?)