Having been both AD and a Reservist, I can say that there are hidden costs with the Reserves that are not being taken into account. Trying to do war "on the cheap" will bite up in the ass eventually, especially now that the reserves have proposed doing a 6 week annual training. Therefore, the cost savings will be made up by the unemployment the USG will be paying to those unable to find work
So that's about four hundred billion annually, or more than a thousand dollars for every US man, woman and child -- but hey, there are all those threats. Uncle Leon says: "We’re facing threats from Iran, facing threats from North Korea, we’re facing threats from terrorism. We’re still in war in Afghanistan. We’re continuing to have turmoil in the Middle East. We’re facing cyber attacks. We’re facing a number of challenges. We have to protect this country. That’s my job. That’s what I’m paid to do and that, thank God, is what the United States military does."