[optionalsquid]

> This is partly because so many things want an account now. I have over 500 passwords saved, it would be straight up impossible to remember unique strings for each site.

I'd argue that it is not just about remembering passwords. A password manager also helps you remember that you even have an account. I have a similar number of passwords stored as you and there's no way I'd remember all the sites I signed up for (never mind the passwords) if not for the password manager I use.

If I was diligent I could probably track them via confirmation emails (or self-authored "confirmations" for services that don't send a confirmation email), but I can guarantee that a lot would slip through the cracks if I were to attempt that.

A password manager also gives you a convenient place to store (and share) secrets, recovery keys, SSH keys, and similar bits of security related information that you cannot memorize.