If we somehow got the political will to enact national legislation calling for high gun taxes and licensing fees, maybe the revenue could be used to fund buybacks. It could become a platonic ideal of a virtuous circle.
Of course, if guns were made too expensive to legally buy and maintain, that would surely precipitate a very active black market for guns, which of course would be bad. But would that create a situation that's worse than things are today? I don't see how that can possibly be.
2A people like to say, "when guns are outlawed, only outlaws will have guns", which has a sort of surface logic to it. But those same outlaws are already getting guns now, and beyond that, it's a virtual certainty that the ease of obtaining guns is leading some people who might be on the fence about which direction their life could go into becoming outlaws in a such a way. In that very narrow sense, it's not unlike the recent proliferation of gambling: the shocking ease with which people can gamble now, on almost literally everything, is making gambling addicts of millions of people who might never otherwise have been exposed to it. It's one thing for someone to work to seek it out, and quite another when someone is constantly being enticed into it.
Which is to say, just because an active black market would spring up for guns, were they heavily restricted, is no reason for keeping guns as easy to obtain as a six-pack of beer.