Actually there has been a downward trend after each "crisis" in bitcoinland. When the Polish exchange went belly up, values dropped, then recovered. Mr. Bitcoin? drop and then back up in 60 days. Mt. Gox 1 & 2? same drop, faster recovery, flowed right into the +$30 halcyon days.TradeHill, Bitcoinica, Bruce Wagner, Puttaya, Zhou-tonging, Intersango, Bitcoinica 2, 3 & 4 (which is also Mt. Gox 3), and the early 2012 Crash all recovered within 90 days after an initial drop.
I believe it has little to do with the supply, and everything to do with the perception. Publicity begets newbies, newbies react badly to risk profiles, flight through fear creates downward trend, smart money snatches up cheap coins, value increases, new publicity begets new newbies and the cycle continues.