I think for national armies which are funded by tax payer money the total cost of ownership should be a significant factor when considering what to buy. And should factor in the definition of "best".
I don't know much about aerial warfare. Aren't fighter jets just glorified missile launching platforms nowadays, especially for defensive purposes? What does the extra cost buy for the end user in terms of actual features they are going to use? I suppose the keyfactor of a multirole aircraft is radar that allows tracking and fire control for both aerial and ground targets and a selection of air-to-air and air-to-ground missiles that go with it. What am I missing?