I've yet to see anyone seriously address the real reason telcos want this, and it's quite unfortunate. Right now the telcos face something they have never had to really face before - competition! From who? Vonage, Skype, etc. The telcos want to marginalize them because they offer competing services to the telcos main business... telecommunications! This becomes a win-win for telcos because they can now charge the likes of Vonage and Skype, making those services less attractive to customers who already have to pay the telcos for their internet connectivity... and if Vonage/Skype don't want to pay, well that's okay too because they can degrade the quality of those services enough to effectivly make them unattractive to customers.
There was an Op-Ed piece in the Wall Street Journal last week from the CEO of Qwest who used the analogy of LL Bean and FedEx saying that a customer pays for the standard shipping to FexEd to receive a package from LL Bean - if LL Bean decided to offer an upgrade to overnight shipping to it's customers for no additional charge, there's no problem with that. I'm disappointed that WSJ did not print any reactions to that because the analogy was clearly flawed.
A better analogy would be if FedEx charged the customer for shipping and then turned around and charged LL Bean again in order for the customer to receive the package telling them "we already got the money from your customer (already paid for DSL/Cable/etc) and if you don't pay us more than the initial cost of shipping (pay for priority/quality of service), packages from you will be put in the back of the line behind all your competitors and we won't even guarantee it will be delivered at all."
Personally, I am insulted. I pay for my bandwidth already. If I want to use that bandwidth to use Google or Vonage or anything else, it's my bandwidth which the telco has already made money from.
They claim it offers more variety to customers - I already have variety! If 1.5mb is not enough, I can pay more and get more bandwidth, so their claim that this adds choice to customers is bunk - we already have choice. This serves no other purpose than to limit our choices to services they can extort or whom they prefer and to help marginalize their competitors at our expense.