Volume isn't just lower compared to post-crash, but also before that:
That's probably because of the recent incidents with regulations. Many people are waiting until that is cleared up before they can confidently trade again on Gox. Until then the volume will stay extremely low, with short increases in volume during price changes.
Wishful thinking, bull.
A more likely scenario is that speculators consider the price too high (potential reward greatly outweighed by risk at the moment), stubborn miners in a more competitive environment are holding positions, stubborn sellers are not willing to go lower than their entry point and there is a much reduced flow of money into Gox for numerous reasons, including potential new investors sitting on the sidelines viewing a stagnant price and considering weaker returns. Doubtful that the regulations are primarily responsible for widespread panic or reluctance to buy in. It is true that the regulations make it more difficult to get money into Gox, but generally only for the criminal-minded. If you have nothing to hide, it is still easy to transfer money, for example via wire.
I would entertain the possibility that recent regulation enforcement has scared away a small minority of criminals who were using bitcoin for money laundering. If this minority was responsible for most of the previous volume and are now absent, then I'd bet on a long, drawn-out downturn.