Because it was half-assed and from canonical.

This article sucks and didn’t actually explain why upstart failed.

Saying it failed because it was unpopular is idiotic. Why was it unpopular? What did other distro maintainers say about the canonical license? Why was Red Hat working on a separate solution instead of upstart? Why did upstart not provide additional features like systemd did? What made canonical pull the plug? There are so many questions and no answers to explain upstart’s failure.

Because SystemD