Define an alternative. Most systemd alternatives do not concern themselves with post-boot event handling much, for example, which is a rather big part of modern systems. Most alternatives do not use a declarative style for unit definitions, which is a safer model being adopted by many other parts of Linux, including whole distros such as Nix.
Things like Kubernetes have become popular for similar reasons.
Notepad.exe is also an alternative to Word, if the subset of functionality you're looking at is strictly text input.
"demonstrably better" ... there's a reason beyond entropy why a lot of distros decided to adopt SystemD. A talk linked to in another thread goes over a lot of this. TFA itself shows there are alternatives.
It's like arguing that KDE or Gnome shouldn't exist as options... nobody removed anyone's options. Don't like it, fork it.
I'm not sure the presenter is condescending enough. Maybe he should have given an abbreviated history of Unix as well, oh wait, he did that.