Enterprise distributions and free software

No two businesses have the same needs. One of the interesting data points for the Frakenkernel is the smaller companies with specialized hardware that is produced in such low volume that creating and integrating drivers is done once a decade or so. They want a kernel that will work with that driver for a decade without changes while they still have the ability to upgrade their environment. The Frakenkernel has a lot of viability in this low use high cost hardware proposition and there are a lot of companies and businesses with this type of specialized hardware.

I haven't looked in a number of years but I thought Redhat offered support on their Frakenkernel and Vanilla Kernels for those that want to run them.

The financial services companies do seem to use a wide variety of distribution and custom kernels (judging by support tickets seen at Solarflare). I'm not sure their rapid upgrade cycles are really a model for anyone else though - there is always a significant cost and risk to infrastructure changes, and the benefits of a minor upgrade tend to be less clear in other environments.

Your two mentioned cases also have a turnover of new equipment. There are lots of enterprises that do system refreshes based on depreciation schedules (3-5 years) and when they do, they buy what is current h/w and put the (then) current versions of O/S and app on top of it. And there it sits for the next 3-5 year cycle. Updates (really fixes) are being applied to a static base. Those kinds of issues are easy to handle. If, however, you have *lots* of systems, think 5-6 digit counts, you are in the position that you are *always* buying new gear. You can't help it simply because of the scale. If you only have resources to rack&stack 2000 systems a year but you have 5-10 times that number in service, you are always churning. You now face the problem of either backport hell to get h/w enablement or you move closer to mainline where that enablement was based. This is a painful place to be which means that there is a scale to "enterprise". RH's sweet spot is the former (smaller case), not the later. And if you are that big, you need to apply the inhouse resources to get closer to mainline. A lot of shops do this but not really understanding the scale issues, do it badly.