I mean systemd didn't force any distro to use their software nor force any other developer to assume systemd is present. Any software that assumes systemd is present is not the fault of systemd itself, in fact I'd argue it is a sign of its success. Argue all you want about systemd being monolithic and single point of failure, at the end of the day, software dev needs some tools, and if systemd already provides it but other software doesn't, of course they will choose systemd.