My guess would be at the next recession. As more people get into craft beer, and it becomes a popular hobby of men in their 30s, more demand and more enthusiasts (men in their 30s with cash to burn) enter the market. Since we live in a very competitive culture, dickswingers will continue to increase in number. I'm sure there was a time where pappy 23 could be acquired for less than two testicles and an arm.
I equate the rare beer market to a certain segment of the art market. I think that there will be a lot of failures in terms of new breweries, but the staples of rare beer will continue to rise in value (unless production for that beer increases). For example, if you are into movie posters, you've seen a massive increase in the amount of new posters done for old movies. (See mondotees.com). Since about 3 years ago, the amount of re-sellers has skyrocketed to the point of most new art being oversold and not holding value. Now those same noobies in the art world want to use their money to buy the piece they missed out on when they first entered the game. They will use their funds to join the rest of the party trying to acquire these prints, and along with the fact that there are less of them being offered for sale, this contributes to the "classics" being held in high value.
Another thing I'm having trouble understanding is why American AWAs trade so high. In my opinion, there are very few that even come close to lambic. Without going into detail, it is pretty easy to pay less for shelf lambic shipped to their door than they would pay for half-assed American wilds. Just my 2c.