This is not dynamic pricing. This is a price ratchet based on diminishing inventory. There may be an algorithm at work here, but it would be superfluous. All they need to do is set thresholds that increase the price over a known quantity of tickets.

Dynamic pricing works as a mechanism to bring more supply to bear. You can't do that with concert tickets. The only way it would work with concert tickets would be that as an individual concert's seats started to sell at a certain velocity, then another concert would be added for the following night. That would bring new capacity online, which would bring the market back in to "balance". This would go until there was no more demand. Their result would be the maximum number of total tickets would be sold at the maximum price possible. That is different from "15,000 tickets sold at the highest price possible".

This is nothing more than a way to disguise a significant price increase.