I mean, saying that any single factor is why you "lose a war" is completely ignoring how incredibly complex warfare is. No one loses a war because of one piece of equipment.
But if we were to take that framework as true, it would be just as fair to say that you can lose a war by having inferior equipment.
There are a lot of factors that go into military procurement decisions. That's a part (albeit a small one) of why they take so damn long.