What more could Jetstar do for pax? Short of producing a new a/c
Well as you asked, I guess they could have chartered an aircraft from one of the many other Airlines to get the pax home, sure Airlines like Thai or Garuda would provide a charter if not Qantas themselves.
Obviously a considerable expense for Jetstar, but they would have saved against that cost all the fares they refunded plus all the other costs incured like accomodation etc, and avoided all the ugly and costly bad press.