This is quite incorrect. First, for the purposes of a recovery plan, each customer is worth a NEGATIVE amount equal to its account balance (that is what MtGOX owes him), plus a positive amount equal to the fees that he is expected to generate over, say 2 years.

IIRC, the sum of the accounts was found to be about 800'000 bitcoins, worth about 400'000'000 USD at current prices, plus a large amount of dollars.  That is the NEGATIVE part.

For the positive part, only active customers count; inactive customers, that do not trade, generate no income. IIRC, according to analysis of the database leak by @rpietila,  MtGOX had around 70'000 active customers, and that with a very generous definition of "active".  To pay 100 US$ of trading fees, a customer would have to trade a lot.  If the NewMtGOX decided to charge significant maintenance fees, most of those 70'000 customers would probably close their accounts.  So this positive term -- the value of MtGOX's customer base -- is very small, maybe only 1/100 of the negative term above.

The significant positive terms in the evaluation of MtGOX are the bitcoins and dollars that MtGOX actually had (I lost count, was it 220'000 BTC?).  Adding everything gives a huge NEGATIVE value for the company.  Who would pay even a satoshi for the "privilege" of having to pay hundreds of millions of dollars of debts?

The Sunlot proposal makes sense for them only because they propose to assume only the positive terms above, spend some of that money for certain expenses, and then perhaps distribute the crumbs to customers, thus declaring the debts extinct.