I wouldn't call the problem "solved" just because of password managers.

Password managers shift the paradigm and the risk factors. In terms of MFA, a password in your manager is now "something you have" rather than "something you know". The only password I know nowadays is my sign-in password that unlocks the password manager's vault. So the passwords to my bank, my health care, my video games are no longer "in my fingers" or in my head anymore, they're unknown to me!

So vault management becomes the issue rather than password management. If passwords are now "something you have" then it becomes possible to lose them. For example, if my home burns down and I show up in a public library with nothing but the clothes on my back, how do I sign into my online accounts? If the passwords were in my fingers, I could do this. But if they require my smartphone to be operational and charged and having network access, and also require passwords I don't know anymore, I'm really screwed at that library. It'd be nearly impossible for me to sign back in.

So in the days of MFA and password managers, now we need to manage the vaults, whether they're in the cloud or in local storage, and we also need to print out recovery codes on paper and store them securely somewhere physical that we can access them after a catastrophe. This is an increase in complexity.

So I contend that password managers, and their cousins the nearly-ubiquitous passkeys, are the main driving factor in people's forgetting their passwords and forgetting how to sign-in now, without relying on an app to do it for them. And that is a decrease in opsec for consumers.