Systemd was initially sold as providing faster boot times. Objections to its cancerous spread to other services beyond init were dismissed without providing any good reasons for why it was necessary or even desirable beyond "we're doing it, quit complaining." The changeover at Debian was handled so poorly and with such rancor that many from there still have a bad taste in their mouths.
Devuan was one response to that, and a good one. Artix was the response to Arch adopting systemd. Slackware and Gentoo and other older distros have stayed away from it. And as another commenter noted, lots of people have abandoned Linux for the BSDs.
The systemd fallout is demonstrating something I always thought was the weakest part of Linux compared to the BSDs, which is that the Linux userland is developed completely independently of the kernel. People do whatever the fuck they want, and frequently the relationships seem to be hostile.
I don't think systemd really solves that problem, either, but rather makes it much more complex and fragile. Hopefully the ecosystem will continue to support non-systemd distros in the long term.
Systemd was not about speed. Speed is a side-effect of correctly handling ordering. See http://0pointer.de/blog/projects/the-biggest-myths.
Everything else that systemd brings is questionable to say the least. Combine that with a project founder with shitty personality and you get what systemd is today.
TBH i think this is its biggest strength because it makes easier for people to switch components that they dislike. After all, you can still use another init system, audio server, desktop environment, shell and other pieces of the userland if you dislike the defaults without having to change the entire OS. On the other hand with BSDs if you dislike something you have to switch to a fork that affects everything.