So they weren't interested in doing a big 200 part mess wherein you couldn't miss 10 seconds of an episode without getting lost. So sue them.
I'm not a fan of long arcs at all, they're too hard to follow if you can't catch them every week. ENT's fourth season hit it about right, but I wasn't able to watch it during first run at all.
All those serialized mainstream shows that always got raves I never saw either.