Hi Jeff:

You wrote a great little article last year on fixing sync issues in Android.  It's an excellent check-list.  However, there is one super well-hidden cause not mentioned that I thought you might want to insert:

Step 1 -- as you've written

SUGGESTED >> Step 2 -- check whether synch is turned OFF globally -- this is unfortunately hidden in Data Usage > Context Menu > Auto-Sync Data

Steps 3-4 -- as you've written.

For what it's worth.  Cheers,
Assad

Ref:
http://webware2.wordpress.com/2013/03/07/sync-is-off-google-android-how-to-turn-on/

Your article:
thedroidlawyer.com/2013/09/how-to-fix-sync-issues-android/