The major difference is that Qantas is well run and profitable in normal times whereas Virgin have lost an average of $215 million a year for the last ten years. Any bailout without a significant restructuring is likely to see the losses continue. When Ansett folded, Virgin Blue was in a position to step into the gap and prevent QF from having a monopoly, this time there is no potential replacement waiting in the wings and given the current financial situation, no one will be wanting to try.
A possible compromise would be a bail out of both airlines, but only to prevent a monopoly which would be unacceptable to the ACCC. The conditions on Virgin might be a cessation of wide body operations, a removal of premium class and a restructuring of the company back to its low cost roots.
A 70/30 market split in favour of QF, who would fly the long haul routes and carry the higher yielding pax, leaving the lower yielding pax to Virgin who would become a Ryanair/Easyjet low cost carrier. Whilst not a perfect solution, jobs would be retained and a monopoly avoided. Losses at Virgin could be brought down to a much more manageable level, there would be choice and some degree of competition in the market.