I'm not a security expert, but I think people shouldn't panic when a security patch comes to the latest OS version but not on the older ones. Maybe the security breach found is only affected the specific OS, not the older. In most cases, you'll still safe by staying on the older OS for the next 2 years if you don't want to update because in the end you'll get about the same level of security. Yes sometimes security patches are delivered later, but I don't think its something an average user should worry about.
That said, in my experience, its worth waiting at least until the x.2 or .3 update before upgrading to the next major OS because since a couple of years (with the exception of Big Sur) there was performance issues or bugs that persisted until that point.