Security patches aren't like bugs or features where you can just roll a new version. Often patches need to be backported to older versions allowing software and libraries to be "upgraded" in place with no other change introduced.
Say you had software that controlled the careful mix of chemicals introduced into a municipal water supply. You just don't move from version 1.4 to 3.2, you fix 1.4 in place.
Yes, if they all just backport security patches we'll be fine. No, people are not going to just.
What you're looking for are Debian stable packages. :p