That's one shitty conspiracy. If this were Red Hat's play, why would they do it with a project that other distros can adopt and have adopted? If anything, providing APIs in systemd makes it easier to migrate to other distros as long as they use systemd. (All relevant enterprise distributions use systemd, i.e. RHEL and SLES and Ubuntu Server.)
Up front, let me state that I have no desire to die on this particular hill, which is why I weasel-worded the hell out of my <conspiracy> block.
However, in this hypothetical scenario, the idea isn't to make it difficult to migrate away from "official" Fedora - it's to make it increasingly difficult to build a distro that is not, fundamentally, Fedora. And if everyone is building distros around Red Hat's quirky middleware, which distro is going to work best? Red Hat's, of course. Who are you going to hire to tell you how to manage the thing? Red Hat, of course.
(The logical extreme of this is the situation with Darwin. OSX's kernel+"middleware" is technically open source, but it's basically impossible to build an OS around it.)
That also makes no sense. Using systemd does not fundamentally turn your distro into Fedora. There are several distros that aren't Fedora that have established use of systemd, and there are several companies selling support offerings around those other distros. In reality, all these distros have come together to work on it jointly as an open source package, which is just a small part of your overall Linux distro typically made up of thousands of packages.
By comparison, I don't believe any companies are selling support offerings for open source Darwin, not even Apple.
Correct, Red Hat will decide the future of Linux userland, not the distros, they will just have to follow. This is a way of building one distro with many flavors instead of many separate distros.