Why do you think, that they can not replace frozen and lost coins ?
As I said, If they sold the frozen BTC on another exchange they wouldn't have any left on Gox to replace the frozen and lost BTC.
The only other option I see is they buy BTC on Gox at a discount, sell them on another exchange, use the profit to buy more again on Gox and repeat until they have enough capital and BTC to reopen withdraws.