One thing to note, you talk about how hashed passwords are impossible to crack, but that is misleading. A number of breaches in recent years have occurred and retrieve passwords that were stored in plain text. Some systems use an inappropriate hash, like MD5.

As another commenter said, using passwords that you can remember is simply impractical at scale. The proble with remembering passwords is that you WILL forget them on occasion, especially as you age. If you have enough money to bank online, you have enough money to use a password manger.