It's one of the most successful advertising gambits I've ever seen by a humble brewery. It's all the right things to do for the producer, creating so much sizzle for their steak and dovetailing with the yelp/Insta/FB thing. Artificial scarcity because they COULD brew it all the time, but when bother when you have so many suckers clamoring for it?
Getting people to stand in line for hours is just legend, advertising-wise. Reminds me of when I worked at Groovy Walnut Square and used to see people lined up everyday for Juice Bar Collective pizza. It was basically pizza toppings (with very good cheez) on a deep dish crust cut in squares. But people were nuts for that. Like the Younger, it was served for a limited time each day and that worked to collect your buying populace and deliver as much as was economically feasible.
Anyway, I did it once and it was unique ale, easier to drink than Elder. But their Blind Pig is my favorite that they brew and you don't have to stand in line for that. Getting people to love the Elder was original proof of their marketing savvy. It's like drinkin pinecone juice while you lick a grapefruit. And the thing is, it basically numbs your tastebuds for a while so the idea of "enjoying it" with your food is fanciful at best. After a while, you aren't even tasting it anyway. But it hit right when people were so eager to do something different. It caught fancy and it's success spawned the Younger.
Oh, and my understanding is that you have to buy a variety pack to get it, so you are trying more of their products. Talk about workin' the customer....