I use systemd across distros, and am now confused when I run into an old SysV system.

When I'm sufficiently advanced to bump into one of these corner cases, it will be a Good Problem To Have.

The market penetration of systemd is about as good an empirical validation as can be had. How soon until it's codified in Posix?

I'll readily admit that systemd isn't perfect, but my overall experience is that it is better in many ways to its predecessors, and did solve real problems.

And when I referred to "systemd hate" I was not referring to healthy criticism, but to those who take very chance to claim that systemd never should have been invented and their init system of choice is clearly superior. Rather than, say trying to make systemd better, or make their init system fix the problems that systemd was designed to remedy.