I am not a systemd skeptic, but I'm also not somebody who cares that much. (Which might seem at odds with this thread, but I'm in
a lot of meetings today. ;) I use it and it gets out of my way. For me, it's fine.
I'm not qualified to judge the quality of the code in systemd directly; I've browsed it a little but I am a middling C++ programmer and while it hasn't stood out to me as smelly I would defer to more knowledgeable heads. I get the drive for very rugged underpinnings, and I'm on board with that; in things that aren't C++ I frequently am the one with the scalpels making criticisms similar to yours, so that totally resonates with me. I am not, however, convinced that any of the alternatives that currently exist are materially better, so I kinda shrug a bit? Further, it seems to me that the generally modular nature of systemd (regardless of how coupled one believes those separate modules to be) suggests that a determined programmer could probably build a drop-in replacement--Rust? Where's my Rust Evangelization Strike Force?--that plays nicely with it and grows to replace poor and soft design.
The social aspect you bring up is, to me, the most compelling argument against systemd (because monocultures aren't great in general, etc.--I think most people agree on that). Thing is, though, I think that that bottom-up consensus model was doomed from the start. I don't think it was ever going to be tenable as soon as there's any money in it. Red Hat wants consistency, their stuff is going to have consistency, you can use it or go off-roading.
I don't think there's a great solution aside from "build your own ecosystem and don't let it get capitalism.txt'd to death." Which is a deeply unsatisfying and impractical answer. And to be clear, people who feel strongly about it should do that. I'm not being snarky when I say that. I'm a pragmatist--if it's better, I'll use it, too, and submit patches if needed and when I'm capable. ;)