I like this writing. Solid.

But, I'm curious: What are the specific deficiencies the author sees in daemontools? "Not ready for primetime."

I mean, it's so typical for bloggers to say certain software is this or that (some generalisation), without giving details.

I don't know much about systemd. I find Linux too chaotic, a moving target that moves a little too frequently for my tastes. It's changes like these that I find take too much energy to follow.

I doubt it's a problem specific to Linux though. As a BSD user, I've been amazed with how much init.c has grown in size over the years. A variety of developers have touched it.