The main problem for password managers is they are too difficult to use. For the average user.
Some websites won't auto fill and you have to manually tell the manager to fill the login. Even worse is when you have to find the password then copy and paste or even manually input.
As for remembering passwords. Sometimes they won't recognize you created a new login and have to input it manually. It will save the wrong info or not update a changed password.
Another issue is password rules. I can see there being different minimums. All websites should allow letters, numbers, uppercase, lowercase, all special characters and no maximum. That way you can easily auto generate secure passwords.
Until they can make at least the detection, auto fill, save and updating consistent. People will shy away from password managers.
Many techies don't understand how the average user uses a computer. When they do something they don't understand what they did to accomplish a task. They just memorized a procedure. Even a slight change causes them a lot of problems.