If adopting systemd actually broke everything, then of course they'd be doing something else instead. The anti-systemd crowd looks at this issue the way you might look at someone who took a working piece of software, and then did a completely correct transformation of all loops and conditionals to use bare gotos.

It's not incorrect to do that. Nothing crashes. It might actually even be faster or use less memory if you were sufficiently clever about it. However, the argument is that you just bought yourself a future full of pain and misery for not a big enough present gain.

Look at poor technical decisions from the past. The earliest browsers were encouraged to be liberal in what they accepted (an adaptation of Postel's law to HTML parsing). I think a lot of people today regard that as a decision that probably held the internet back by a decade -- think of the time we wasted writing compatibility layers and artificially restricting what our web pages could do. But it wasn't immediately obvious that that was the case. It took 10 or 15 years for the implications of that decision to really hit home.

What happens next is not a collapse of the world. It's a slow accrual of follow-up decisions that are needed to keep the lights on, until one day you look at the Eldritch horror you've had to build over 10 years and go, "Jesus, that was a bone-headed idea." Maybe they're completely wrong in opposing it, but systemd isn't anywhere near old enough to have decided that just yet.