It did not double in terms of weapons procurement. Military spending mainly increased du to operations cosst
Procurement is actually a small part of the budget. By far, the majority of the budget (around 75%) is in pay, benefits, medical, housing, and training.
And most forget that when we are training in the field, we use generators. We saw our training decrease to almost nothing in 2009, especially when the price of gas skyrocketed. A PATRIOT unit in the field will typically go through well over 1,000 gallons of diesel in a day, as it required multiple generators to function (especially the massive 150 KW power plant that powers the RADAR and command van.
Prior to President Obama taking office, we went to the field for 1-2 weeks on average 4-6 times a year. But when we did our pre-deployment training, we spent it at a set of buildings, there was no money to do real training. And when we returned, all of our training was in those same buildings. Once again, lack of funds because there was no budget and we were under sequestration. We were often even doing training with the equipment of another unit (or they would do it with ours) because a lot of our stuff just did not work.
And the thing is, things are still like that to this day. And a lot of the military gets hampered by things like high gas prices, because they have to factor that into their budget themselves. They do not just "get it for free", and everything in a military unit has to come from their own budget. And training is expensive, but it has to be done.