Shuttleworth's misplaced example of cadence

my understanding is that the distros are down to a 'couple hundred' patches to the baseline kernel. This is an order of magnitude or two fewer changes than between kernel versions (and generally much smaller changes)

the question about long-lived kernels is interesting, but I suspect it's still smaller than between mainline kernel releases.

Also remember that the patches are all available, so the distros can and do see what each other are doing (and there is cross pollination between the kernel teams in some cases) so I suspect the differences are smaller than just counting the patches of each distro and summing them up.