It takes 10-20 years to field a capable modern weapons platform. It would be ridiculous to wait for the fight to be joined before developing your platforms.

The air Force joke is "it isn't your Dad's air Force, but it might be his plane." Service lifetimes of some craft are past 50 years.

I don't mind a done war that field tests all of our systems, kills a slew of bad people, and costs us no blood. That's a good deal to me.