Well, here's the problem.
(Before going any further, let me first say that I agree with blackadder; this seems to be a payola issue. The rest of what follows is mostly theoretical. I believe our system to be more corrupt than any of us truely realize. We play the parlor game of pretending esoterica matters, when in truth it's simply about who gave money to who).
The throttling back and pay-for-extras that have been attempted thus far have been rejected by the market. In principle, the solution to companies attempting such policies should be competition.
As Bronco noted, however, there are barriers to entry in the field. There are only a few ISPs, comparatively speaking, and their networks were funded in part with government dollars (at least that's my understanding of it).
While on the surface net nuetrality seems like something everyone should support, it's still dangerous. It's allowing government a foothold and measure of control over something where it previously had none. While the current level of control seems innocuous, it's setting the precedent that the government has the right to stick its nose in this business.
Nothing with government ever stays innocuous and harmless. Time will pass, and government will continue to creep.
My specific problem with this issue is the barrier to entry for competitors. There doesn't seem room for a Netflix to come along and kill the Blockbusters of the ISP industry if they decide to collude to rake us over the coals. Then again, I never would have predicted Netflix owning Blockbuster the way they have. So who knows.
I'm torn. The government regs seem harmless at this point, and I despise the ISPs for even considering such policies. I have to believe, though, that we've built enough history that customers won't stand for throttling back or other usage fees, and that some competitor could come in and make a fortune offering real Internet service.
But then I go back to the fact that most of the infrastructure is owned by only a few entities, and that worries me.
In the end, I don't trust that these politicians have our interest in the front of their minds. I don't want to see the government gain a foothold and implicit authority and stewardship over the Internet.
I think I'd rather take my chances with the ISPs. But they are dirty dealers themselves, and quasi-governmental.
I'm far from an antitrust expert, and I have no idea how much actual control Comcast et al. have over the infrastructure involved here, but your post reminds me of three major components of the US antitrust landscape: 1) essential facilities doctrine; 2) concerted refusal to deal; and 3) the break-up of Ma Bell.
I think Net neutrality is all well and good, but I'm unconvinced we face a monopolistic hellscape if it ultimately falls. Maybe I'm wrong; maybe the idea that we'll see MCI-style competitors backed by the specter of antitrust penalties is Pollyannaish. But it's that or trusting our politicians to perpetually protect our interests against encroachment by one of the largest industries in the country. I think I'll take my chances.