I'm going to sound typically cynical here, but the voting masses are malleable and tend to blow with the wind. To the average American, the Bush administration was an unmitigated disaster (actually, I would agree this, though not for the reasons that most would cite - I was and am most concerned about the unchecked spending and the expansion in the size and power of the federal government - that administration was hardly "conservative" by any traditional measure). If we were presently in a time of unprecedented prosperity, you could say with absolute certainty that we would still be run by the same general group of people - Bush could practically have painted portraits of himself on federal buildings and his designated successor would still have been elected. Instead, we suffered a nasty economic meltdown which was driven by factors not directly under the control of the federal government (to suggest otherwise indicates a gross misunderstanding of basic economic principles). The housing and credit crisis are closely related, and there is actually some evidence that government intervention in the markets exacerbated that problem. Nevertheless, I digress.
Given the state of things, people were easily moved by the idea of "change," which is precisely the idea that Obama rode to victory. Really, few of them understand the fundamental differences between the two political parties, if indeed there really are any (note, again, the Bush administration's massive overspending and government expansion).
Frankly, we as an active political group absolutely dwarf our opponents - compare the size and wealth of the Brady Campaign or similar to the NRA, for example. There is no comparison. However, we are also far smaller than the politically apathetic masses, who don't care one way or another and are, as I said, easy to manipulate. There was actually little to no protest when the Clinton AWB expired in 2004, and there is likely to be little or on protest if a new one is put into place. Either way, these people simply don't care. Gun control is scarcely a footnote in the average voter's mind - and given the political alliances that anti-gun activists have built, it's easy enough for them to push their agenda when the right people get into office without raising much protest amongst the constituency. People did not vote for Obama on the basis of his purported gun control policies - many probably don't even know what they are (in fact, they were buried even on his campaign website) - but nevertheless, it is what it is and we have to deal with the potential consequences. Remember: it isn't the will of the people, it's the will of the people who participate. 99% of the country could oppose gun control, but if the 1% who didn't were running Congress, we'd be SOL.
Right now, I'd say that we are actually in the the stronger position, given the Heller ruling as well as the prevalence of CCW and the proliferation of castle doctrine - but we can't rest on our laurels. I would not be surprised to see some attempt at a renewed AWB (a classic political football in modern times) or some legislation aimed at gun/ammo registration and various taxes on ammunition or firearms themselves.