I wonder why. There seems to be a huge gap in the market for a professionally run enterprise here. Or at least, anything more focused beyond students half-assing it part-time.
Bitcoin market activity may not be large enough to ever pay back the significant cost of building a secure exchange. Also, as TradeHill and CampBX discovered, people just won't move off of MtGox no matter how bad it is.
People won't move off of MtGox for a simple reason: it has by far the best liquidity.
The only way for another exchange to get a foothold would be to offer similar liquidity, which would mean taking the other side of most trades themselves. This would be very risky and they would need deep pockets.
