I think I might have some explanations. I went to this website
and put the manufacture date as 8/15 (4 months from the best by date). It said that the yeast were 35% viable. With your starter, that should have brought your cell count to 100 billion if you shook it intermittently. Your yeast was pretty old, so you probably under pitched even with the starter. The pitch rate calculator says you needed about 182 billion cells (assuming a 5 gallon batch).
I'm curious about your starter. How much DME did you use? Did you swirl it all during the 3 days?
Also, you shouldn't use an airlock for your starter. It needs the oxygen in order for the yeast to grow rapidly. Covering the vessel with foil is the way to go.
You should pitch your starter at its peak of fermentation. I find that for me, that usually occurs at about 20 hours after making the starter.