Great success and accomplishments usually result as a result of overcoming great challenges. Our American predecessors tamed a hostile continent. Had they been protected by a federal nanny state we’d still all be huddled along the east coast. All those nasty wild animals, misunderstood Indians, unbridged rivers, “unsafe” modes of travel. Lots of icky stuff.
Challenges and struggle results in growth.
War also has a net benefit as long as the good guys (in other words Conservatives) triumph. Much of today's technology emerged from war such as research done by DARPA. Innovation is a useful by-product of war.
But at least it gave birth to capitalism, which saved the day...and worked like a charm to this very day.