By comparison, if the US products fail, there's no real negative effect on the mainland United States.
It's even worse than that. Schedules slipping and cost overruns are good things for the manufacturer, because they can charge more on top of their initial contract. Cost-plus ftw.
But you still run into similar issues regardless of the contract structure. Try and build a rail network without anyone in government wanting something changed from the initial design for 20 years.
Most are paid to prevent projects with a given defect type from proceeding. They aren't rewarded for the number of projects that succeed without defects. Preventing CYA from running wild is a legitimately hard problem to solve.
Well yes, that and the fact that cheap drone guerilla tactics have fairly recently become a technological possibility. Remember that Ukraine is actually a bit late to the party here, with Hezbollah and ISIS having used cheap drones with cameras and/or explosives tied to them years before Ukraine or Russia did. The asymmetry in cost between those cheap drones and the existing "more hightech = more better" militaries were (and are!) used to was already established. That a party such as Ukraine faced with a more advanced and much larger opponent would lean towards such an approach makes a lot of sense. Ukraine did not (and does not really) have significant amounts of the traditional stuff.
Now given that they chose that path, they have been very effective recently, but note that the tethered fiber-optic drones were a Russian invention. So even that deeply corrupt, large dinosaur of an institution innovated significantly. It is also important to note that a significant part of the recent successes of Ukraine are due to them having Starlink access and Russia no longer having it.
I'm not saying the sheer will to survive or the inventive organisation of the Ukranians did nothing (far from it), but I do think it is a mistake to think that their success should only be viewed through that lens.
Ukraine fights back or they lose their sovereignty. Most of the conflicts the US gets into, it's entirely a choice to put soldiers at risk.
So yeah, the evaluation of war effort will be different, because the situations are completely different.
Startups = have few resources, product has to work or company dies
Big tech = minimal cost of failure, instead minimizing risk
And yet this mechanic is also why startups are able to innovate and bring new products to market so much faster.