Maybe it's distro specific but I'm fairly sure mysql by default installed with skip networking around 2012, and with bind-address set to localhost since then. Also the root user is only configured from local by default but I'm not sure if that was true 14 years ago.

If the defaults are more secure than your examples, it's not fair to blame the database or the defaults.

And personally I hate it when software forces security requirements on me. Maybe I don't need an admin password. It's one reason I gave up on selfhosted gitlab - there was no option to reduce password complexity for my users, and those users were only connecting from the local network. The other reason being that it spammed 100GB of logs in a month and was using 11GB of RAM before I'd even gotten around to setting up the first repo.