I bought a house that had a bunch of broken sprinklers, as evidenced
by puddles of water. When I dig down more than a foot for each one, I
find they all have this horribly complicated plumbing arrangement.
http://picturepush.com/public/7728890

It's easy enough to repair, as I can simply match parts at Home
Depot,
but I was wondering WHY there are six or seven couplings where just
two or three would work just fine (seems to me).

Maybe I'm missing something important.

Is it normal for typical lawn sprinklers to look like this?
http://picturepush.com/public/7728891

Why?

thats definitely presidentionally engineered, get rid of it and just
use schedule 40 PVC