Compare that mentality to trying to get a big new subsystem into the kernel.

Torvalds is likely to require you to hammer out all the details and debugging in a separate tree. This even more so if it is replacing a tested, stable and maintained subsystem.

As such, it is the Systemd proponents that should be doing a fork. And run it alongside stable for a time to demonstrate that it works. Then people can move over at their own pace.