I thought Virgin were a budget carrier?
Qantas is a premium airline and you pay through the nose for that but you are looked after far better with them if there are any problems. Wont happen with Jetstar though.
When I worked for AaE, 50% Qantas, there was a plane hangered in Sydney on Christmas day. It had a standby crew, all just in case they needed a replacement aircraft somewhere.
That would cost tens of thousands of dollar but customers wouldn't have to wait for to long. You only get what you pay for.