It's disingenuous to say that /sbin/init (machined/main.go) is less than 400 lines of code. Sure, that file is. What about all of the in-tree modules that are being imported? A super lazy summing of Go lines in the master branch of the repo:

$ find . -name *.go | xargs wc -l | tail -1

  354085 total

Heck, there are almost 100k lines under internal/app!

$ find internal/app -name *.go | xargs wc -l | tail -1

  96885 total

I'm curious what argument you are making here with regards to the number of lines in a single file.