Jetstar delivers a product. If that product were to change, so would the service and standards delivering the product.
As would the cost base of the business delivering that product. i.e it would increase in the Jetstar business. So, If Jetstar were to "become the new Qantas" i would bet it's cost base would be similar to what Qantas' is. Wages to pilots does not a low cost base make.
My money is on Jetstar being Jetstar and a leaner Qantas being Qantas.