This has a lot to do with the junk that loads them down. Most conventional officers work from the mind set of better carry it just in case you might need it. I've seen officers order their troops to carry 60 lbs rucksacks loaded down with cold weather gear (it was summer), tents, sleeping bags, etc. for an assault on a hill that would take at most 2 hours of movement and 1 hour of assualt and fortification. This, dispite having trucks available to carry their duffle bags for excess gear.
Few if any conventional officers see the need to train their troops for stealth or close combat. Stand back and let the artillery and Air Force pound the enemy to pieces and then we will pick through what is left is the motto of most officers today. While that works in a hot and heavy war, it often does not work with unconventional forces. Just my .02
You said a mouthful. First: It is unfortunate that the command structure does not contain more officers with unconventional backgrounds. You can't train/plan/do what you don't have a background for. Second, there is such fear of the viet-PR backlash of losing men that the commanders recoil at the suggestion of using troops where bombs will do. I suspect that more covert stuff than we need to know about is going on in the new theater but I also believe that there should be more. I think we could have accomplished more with well trained SO forces (including RECON) than has been accomplished with billions of $ in bombs. Especially when it comes to getting hands/blades on particularly slippery turbans.