It's certainly possible to build infrastructure to automate compiling, testing, and pushing out a new kernel, but very few organizations are going to justify that much development effort just for security reasons. If you're already building your own kernels because you have other technical reasons for it, and therefore have already put this effort in, then yes, just turn off CONFIG_IP_DCCP and call it done.
I used to maintain a laptop with two user accounts, one of which I used for running sudo and doing important work, and one of which had the Flash and Java plugins enabled and was used for Pandora, YouTube, etc. It sorta worked, but it was a pain, and I eventually gave up on it. If you do have a setup like this, then caring about local root exploits starts to make a bit of sense.
I now have a Chromebook, which sandboxes any attacker-controlled executable code on the machine. If you actually care about the security of your personal computer, do that, or get Qubes or something—and just use the vendor's provided OS and keep it up-to-date.
As soon as you've administered 10+ servers at the same time, your patience for variation from the norm and manual patch building goes way down.
Once you've administered 100+ servers at the same time, any thoughts of doing that go right out the window. along with the person that brought it up.
At that point, any changes are diffs applied to the original package (or a brand new package from scratch) that you put in your local repo. Kernels actually get updates fairly often, which means you either have a lot of work, or you ignore the non-essential updates. Neither are ideal.