Why?

I can understand why people in positions of power might want to disarm those who they lord over, lest the less powerful people revolt.
I can understand why victims of violent crime might think it a good thing to disarm everyone except the police and military, so they (and others) don’t get victimized again.
I can understand people who genuinely believe that “guns = violence”, and think that by lessening the number of guns, they can lessen violence.
I certainly disagree with such positions, but I can understand why someone might hold them.
What I don’t understand are people like the Brady Campaign and the VPC.
It’s not the money, as most of it seems to go toward various lobbying efforts. It’s not the fame, as they’re rarely mentioned in publications, and most people don’t seem to really care as much about them as they do about some bimbo from Hollywood. Even if they succeed, they’re not personally going to be in a position of power over others. It’s not the pursuit of truth and justice, as they intentionally make misleading claims. (When’s the last time a .50 BMG rifle shot down a commercial airliner? How often do criminals use AR-15s to commit crimes, rather than cheap, disposable, often stolen handguns? How often do criminals buy their guns over-the-counter at gun shops or gun shows?)
Why do they do it? What’s in it for them? What motivates them to wake up every morning, go into work, and try to ban guns? Assuming they succeeded and all guns were banned, what then? What would they do?
Coming from my side, I’m working to defend a right that’s rooted deep in history, a safe, fun recreational activity, a means to defend myself and my family, and, if the need is dire, to defend against tyranny. I have a day job (two, in fact, in addition to being a full-time student), and don’t work to protect my rights full-time. If the pro-gun side succeeded in their goals (not that anyone can succeed in defending a right, but let’s just assume one could for the sake of the exercise), my life would change very little. I might have a celebratory range day and maybe buy a new gun, but otherwise nothing major would change.
At the risk of tooting my own horn, I don’t consider myself to be an unintelligent man, but I honestly can’t see why they do it.