It took work because systemd (more precisely logind) solved real problems and so the work had to be done again for the sake of non-systemd distros.
Can you tell me what problems logind solved? Because on my own machine, I don't have it, and I don't need it. In fact, it's a struggle to make sure it's not pulled in as a dependency of anything.
The fact that it took _work_ to get GNOME to run without systemd is a bad thing in my book.
Also, to claim that systemd was selected on merit without anything backing up the claim of "merit" is disingenuous; plenty of worse solutions end up winning all the time.