Building kernel within LinuxCNC

I tried searching for this topic and didn't come up with anything so I thought I would post my question. While I've been a Linux user for a while now, I'm still learning how things work. I know parts of LinuxCNC have been written with real time extensions so it requires a real-time kernel to run properly. Has anyone ever tried to compile the kernel directly into the build of it? Or is this even possible? I kind of got it working on a low-latency kernel, but not sure if it fully works as I don't have a way to test it. Why is this so hard to install on newer versions of Linux?

I think part of the reason real time kernel development lags so much is simply lack of interest (or insentive). There are very few people out there with the knowledge and time to devote to developing RT patches for new kernels.

So the rest of us lowly laymen soldier on with the proven pre-compiled kernels that we can get.