The Russian T72 is a pretty frugal tank as they go and yet I don't recall very many successful armored engagements when USSR was active in their version of Vietnam. Does either the Taliban or AQ have armored forces? Tanks should only fight tanks, otherwise they will fall victim to dismounted infantry who can best use the terrain to advantage. Infantry is better supported by IFV's instead of heavy armor, which allows them to remount and bug out to a better terrain feature or to take cover under the vehicles weapons. OTOH, if I ever had to fight in a tank (I did a rare branch transfer to armor from infantry late in my reserve career) I'd ONLY want an M1A2 Abrams. Gas hog or not, it's still the best tank on the battlefield.
Think the squids are up in arms over a Gates RIF? Wait till Uncle Sam's Misguided Children get wind that Gates and OBOZO are plotting their literal DEMISE. The feeling is the the USMC is an answer to a question no longer being asked. Just wait.
USMC will always be vulnerable to that "feeling". From a beancounter's or pacifist's POV, it's hard to argue that USMC does anything that USA, USAF, or USN can't do. The same argument can be made against NavAir, although it's a bit more of a stretch.
I disagree STRONGLY with that POV.
But I'm neither a beancounter nor a pacifist.