IMHO if Gox is dying their actions have been in the best interested of Bitcoin.
Absolutely incorrect. Mt.Gox has time and time again lied and manipulated their customers. First they had the CoinLab suit, where they didn't even try to keep their end of the agreement. Second, they get their accounts frozen by DHS because Mark Karpeles said that his accounts were not being used for "currency trading, or money transmitting." Third, US dollar withdraws are prohibited because Gox didn't bother to think about legal ramifications. Oh and on top their inability to legally comply with any agreement or financial law, their trading engine had lag times of an hour at Bitcoins peak! All they ever cared about was money, they never cared about improving their product, and they didn't care about their customers. Who here can say they love Mt.Gox's support line? Have you ever seen Gox at any of the Bitcoin conferences?
Let's say they realize they are insolvent and no way to pay back:
Option 1) They suddenly announcement their bankruptcy in their "prime" while having a 70%+ market share. Bitcoin would have absolutely bombed (we are talking single digits)
Yes, you are correct, but the other exchanges should be able to absorb some of the volume and mitigate a total collapse.
Option 2) They stall/delay/lie over the period of several months and their market share slowly disperses to other exchanges. Users slowly get used to the fact that Gox might be in trouble. After a while people expect that Gox is in trouble. By the time they finally announce their bankruptcy everyone will be expecting it, and while their will be a lot of any people still left in that 40% market share, and it will affect the price of Bitcoin as a whole, it will not be anywhere near the disastrous results of option 1.
The only reason why the would be stalling is a.) they raided customer fiat accounts and are trying to bolster their liquidity through that or b.) they are using the spread to generate profit before their final collapse or until they become liquid again. Oh and they still aren't legally allowed to send wires in the US, and they have a $75 MM lawsuit over their head!