This is a common misunderstanding, an OS that receives frequent security updates is a very good thing. That means attention is being paid to issues being raised, and risks are being mitigated. Security is not a 'checkbox' it's more of a neverending process because the environment is always in a state of flux.
So to flip it, if an OS is not receiving updates, or not being updated frequently, that's not great.
What you want is updates that don't destabilize an OS, and behind that is a huge history and layers of decisions at each 'shop' that runs these machines.
Security is meant to be in layers and needs to be built in.
> but it still doesn't work.
It does work because the 'scene' has been silent for so long, but what we as humans notice is the incident where it didn't.