What I think this article lacks to mention is the effect of newer kernels on userspace. While in theory kernels do not break binary compatibility, in practice means that if you switch kernels, a bunch of user-space tools need to get updated. Even up to udev and Gnome integration.
We, at the ELRepo project, offer backported drivers for RHEL and RHEL-clones (like CentOS, Scientific Linux and Oracle Linux) and one way of getting people to test newer drivers for us to backport is by providing mainline and stable kernels for RHEL. Our experience from testing these mainline kernels on RHEL5 is that the removal of certain infrastructure (in a specific case /proc/acpi entries or /dev/rtc nodes) would lead to various problems in userspace. For more information read Akemi Yagi's well written article "A kernel too far" at: http://blog.toracat.org/2011/03/a-kernel-too-far/
We did report those issues to the kernel developers, but there was little interested to get this fixed.
And while it may be easier for SuSE and Oracle to contain such problems in userspace than it is in kernelspace, in the long run even this is unsustainable and forward-porting older infrastructure may be necessary to avoid having to upgrade larger software parts. I look forward to the next 5 years and see how this plays out, but at least Red Hat's way of working, while expensive and tedious, proved to have worked out well. Oracle will have to give up its RHEL compatibility at some point though in its 10 year life-span.
Either you are leading the way or you are following, trying to manage to do both will tear you apart ;-)