The flip side of that is what our current set of telecom ISPs are doing. Imagine getting a non-exclusive contract with UPS for package deliveries. How would you react to your UPS deliveryman stealing packages you've received from FedEx or the post office and keeping them for a few days to slow down non-UPS service. When they do finally pass them through you might only get half the package. Occasionally they'll just set the packages on fire on your front yard just to show you who's boss.
I pay my ISP to transmit bits, not to kill some of them to convince me to use the ISP's paid service. Can you trust your ISP to deliver a streaming NetFlix rental over the net if they want to sell you the same service for twice the price?
Speaking to the actual question of net neutrality: While I agree in principle with the idea that you ought to actually pay for the bits you have delivered and send, in practice this isn't really a market solution for numerous reasons, not least of which is that I cannot deny delivery at my end; therefore advertisers and spammers are free to deliver content at my expense. More importantly, though, is the fact that the largest suppliers of broadband are monopolies and there is not, in many areas including mine, the ability to seek a cheaper, or more reliable, or ... whatever .. alternative ISP. Even in some large urban markets there are no more than two high bandwidth providers. I wish I had as many choices for my ISP as I do for my VOIP. Until I do, I don't see how any sensible person can support "net neutrality." There's nothing neutral about allowing the single-source of a commodity to charge whatever price -- or provide whatever service level -- they in their protected and infinite wisdom decide is acceptable.