Nothing prevents you from maintaining nommu as a fork. The reality of things is, despite your feelings, people have to work on the kernel, daily, and there comes a point where your tinkering needs do not need to be supported in main. You can keep using old versions of the kernel, too.

Linux remains open source, extendable, and someone would most likely maintain these ripped out modules. Just not at the expense of the singular maintainer of the subsystem inside the kernel.