You may need to check if your sshd is using the configuration of /etc/ssh/sshd_config. I have come across such a situation when I upgraded openssh from source with default compile options. After I installed the new sshd I find that the password authentication is enabled no matter how I edit the /etc/ssh/sshd_config. When I run sudo sshd -T to check the configuration, I find that it loads configuration from /usr/local/etc/ssh/sshd_config. I just share my experience here in case some one may encounter the same issue.

There is one possibility that your sshd doesn't read configuration from /etc/ssh/sshd_config.

You may need to check if your sshd is loading configuration from /etc/ssh/sshd_config. I have come across such a situation after I upgraded openssh from source with default compile options. After I installed the new sshd I find that the password authentication is enabled and cannot be turned off no matter how I edit the /etc/ssh/sshd_config. 

When I ran sudo sshd -T to check, I found that it loads configuration from /usr/local/etc/ssh/sshd_config.

This may not be your case, but I just share it here in case someone eles may come across the same problem.