OMG OMG OMG the BZP analysis is done! That's 4 months worth of my free time, gone in one hit of the send button.
The one-line summary of that 4 months' work goes: "People stopped taking BZP because it was shit and once BZP was illegal, MDMA came out better in the cost benefit analysis so they just didn't bother to pursue it."
Which we already knew. But now there's research to back it.