"freeze and backport" won't be going away soon.

One of the issues with 'enterprise' customers is that one size does not fit all. While trying
to run RHEL-5 for like Dreamworks is a pain because of kernels and other code... there are
major customers who are not moving off of RHEL-2.1 until 6 months before its end of life (and
some will just run it afterwords as they are running Red Hat Linux 6.2 boxes still). The
biggest issue is how much money the customers are willing to expend to stay at something for a
long time. 

Some customers will spend quite a bit if you count the number of industries that are still
using old versions of VMS and paying HP or whoever lots to keep it updated. Of course that
number in size of systems is quite a bit smaller than those running the latest Ubuntu
release... so