go back and look at what was supported in Dapper for those 5 years.
I believe that it didn't include 'desktop' things, only 'server' things
also look at how much (or how little) is supported in the RHEL2/3/4 releases over time.
some parts of the stack are pretty stable, these include the kernel, webserve, and sysV init.
other parts are very unstable, and maintinance of 'frozen' ports is not practical. These include Firefox, Gnome, and probably, given it's current rate of change and development, systemd init and udev.