Not a "bloated, monolithic system"?

You're comparing apples and oranges though. Both Upstart and classical init have smaller binaries because they offload functionality to shell scripts which in turn call various binaries to perform simple tasks such as parsing command line strings and writing logs.

So, for a fair comparison, you should include the various helper tools which Upstart and init need to call in order to achieve the same or similar functionality as systemd.