> I feel like it's extremely common for the autofill to not work for various reasons even when you aren't being phished.

This is how Troy Hunt got phished. He was already very tired after a long flight, but his internal alarm bells didn't ring loud enough, when the password manager didn't fill in the credentials. He was already used to autofill not always working.

This is why I haven't bothered with them (the browser extensions; I have used password managers for years and years) and thus why they weren't there to protect against the attack.