Two important ones are that the defense contractors are jobs programs, giving good salaries to skilled workers and investing in education distributed across the country. They are also defense preparedness programs: we buy and build constantly whether or not we need things right now because when we do need them, we don't want to build knowhow and whole industries from scratch.

Claiming that it is all being done well is of course absurd, but it is also very hard to build programs that last for decades and through many administrations, many political changes, involving millions of people. And folks are always eager to point out "failures" that aren't always a sign of anything being done wrong, especially from people who have little idea what it's like building an enormous ship/plane/weapon meant to be serviceable for half a century.