It's a guideline and spending money does not magically solve problems. The fact that the USA as a complex, bloated, bureaucratic military industrial complex does not mean that it's the right way to build a military.

All the money the USA spends on its military and after 17 years they've failed to suppress and army comprised of hastily-trained insurgents armed with 70 year old rifles and rudimentary explosives. And this is hardly the first quagmire of this sort the USA has been involved in.