The primary developer of udev is one of the co-maintainers of systemd upstream and hence they are working together on some changes. This isn't forced on anybody anymore than any other upstream choices in development is. Distributions are free to patch it back or reimplement interfaces as they already have and systemd developers go out of their way to document these interfaces and provide a stability promise to make all of this easier.
It is arguable that systemd isn't crucial infrastructure yet but I dont consider it valid to argue that dbus isn't for desktop linux. All major desktop environments and several critical desktop applications depend on it. Note that systemd depends on the dbus protocol and not the daemon. Android certainly doesn't count as evidence for that considering that it is a entirely separate ecosystem that shares pretty much nothing other than the kernel.