Stable backports of subsystems

> Why is it that the customers of "enterprise" distros want to keep the kernel version stable at such a great cost?

Because there is a whole ecosystem of enterprisey apps and other out of tree modules certified for specific kernel versions, and it’s too much pain to wait for every single supplier to recertify all the bits used in a single system for a new version, hope they land on the *same* version, and then pass internal ITIL deployment checks that the update won’t break something business-critical.

The main reason Red Hat still uses its own enterprise kernel is that it has built over the years commercial links with most of those suppliers and provides the social service of herding this particular bunch of cats (basically, every single company and university which is uncomfortable working directly upstream). The main reason Oracle Suse and others are dropping enterprise kernels is that they’ve been unable to build the same network of relationships (Oracle tried to piggy back on the Red Hat process and Red Hat retaliated by stopping the release of its enterprise kernel as a convenient patchset).