There are some key differences between Debian and Ubuntu as far as the kernel and kernel contributions go.
Debian kernels are really, REALLY close to mainline kernels. They sometimes contain backports of patches that are not in mainline yet, but have been already accepted for eventual inclusion. And the rare Debian-originated patch is almost always sent upstream nowadays (I am not sure it was like that a few years ago, and sometimes the patches are not ACCEPTED upstream but still remain in the Debian kernel).
Ubuntu kernels have a lot more custom changes inside than Debian's as far as I know (they certainly used to), and you WILL get a major black eye when you do that and don't send your changes upstream. I am not sure if Ubuntu still deserves it, but they DO have a reputation of not bothering to send any of their kernel changes upstream in LKML (and that reputation obviously falls on Canonical shoulders).
Also, most Debian people I know that happen to also work on the kernel (and that includes myself!), do it directly *upstream*. Our work almost always gets into Linux mainline well before it ever makes it to any Debian kernel. Since Debian simply doesn't pay anyone to do any work (it is 100% volunteer-based), that work is NOT credited to Debian by most (any?) of us kernel developers that are also Debian developers.
For reference, you could credit something like 200 commits from me alone to Debian's name (I didn't check the date of the earliest commit, so some of those might be too old for the time-frame GregHK is using)... and I am not even one of the most prolific Debian developers that do upstream kernel work, AFAIK.
In the end, we Debian developers [that don't do kernel work in paid time by someone else] work upstream in the kernel without crediting Debian, and Debian nowadays doesn't have much to send upstream that is not in mainline. The obvious result is that Debian has a low patch-count.
THAT is why nobody is on Debian's case for a low patch-count. It isn't low at all, if you consider the "Debian developers doing work in the kernel the same way they do work for Debian", and that it is all unpaid work.
On the other hand, I *expect* Canonical to have a rule that anyone doing upstream work of any sort during paid time by Canonical, must do so using an email that credits it to Canonical. I am certain that RedHat, SuSE, Novell, IBM, Intel, and all others HAVE such rules in place.
So one really can't compare the Debian patch-count to the Canonical patch-count in any way that is even remotely favorable to Canonical...