You're making absolutely no sense. Additional troops have served no purpose since the end of combat operations against the former Iraqi Army.
More to the point, it wasn't Rumsfeld's decision to keep troop levels where they're at; the commanding generals had that authority delegated to them.
Horse doo-doo! Commanders had to "go to war with the Army they had" (his words). Commanders request more troops at the price of their career. Also, there is a money issue here, if you want to know the truth...the average E-3, when I was in the service (late 60s, early 70s) made barely $130/month, had no wife, and no vehicle. Today's all-vol troop enlists for a bonus and makes in the high $20K range, has a family, prefers to live off base and probably two vehicles. That was basically what was driving the train, that and maintaining Bush's promised tax cuts. So, though the genie was out of the bottle as far as wages go, we needed to go back to a draft with a minimum wage guarantee only to get back to a 4 million man Army. No one had the guts to fight for it.