The problem is that of financial opportunity cost: the money keeping the "tank line" active by ordering excess tanks would likely be much better spent on other programs (or even merely not further ballooning the debt). Spending the same amount of dollars on funding the IRS, GAO, SEC, FDA, EPA, or even the USGS or NOAA would likely see much more direct benefits to US residents. Even direct assistance like food stamps or section 8 rent subsidies has a much higher multiplier than spending oodles of cash ensuring the US is ready to defend its hegemony.