|From flickr user Aeter|
A few weeks after Crius was released we saw a surprising and rapid drop in the price of the most commonly used drone, the Hobgoblin II. I asked around a couple of industrial buddies to see if they knew why this had happened, but nobody did. I suspect, though, it's a simple case of supply and demand. The demand has stayed the same, but the supply must have increased.
The new industry interface makes it much easier to explore your industrial options and I think it gave a lot of people the idea to try some T2 manufacturing for themselves. Hob IIs would be a logical choice; most people can either use them or assume they can sell them easily. What puzzled me at first was the delay...why did it take a few weeks for this glut of drones to arrive? Training! If you weren't already able to make these, there's a few skills you need to acquire before doing so. I think enough people buckled down and did the training, then invented the BPCs, then built the drones to result in the wave we saw.