Bandwidth is more than equipment, it also involves laying cable and only so much info can go thru before they need to add more. If it is so easy and there are no concerns then why did AT&T go to rated data plans?
You also mention comcast throttling the applications, that is the point. End users want more applications and the bandwidth to go with it. Comcast was questioned for doing that because of that simple fact, users want more applications to run on the hand held devices, not having a provider dicatating to them what applications they can use. Your argument is not reasonable, IMO.