Sure "They", who ever they are, might want it. But it won't happen. At least I don't see how. For starters, a hell of a lot of democrats are also gun owners for example. Second and that's more important, the idiots that claim AR-15s or comparable weapons should be banned are like an incredibly small minority. Yes, they vocal - right now - but no sane constituent democrat or god forbid republican, will follow that. What it comes down to is political power. And when you look at it the NRA and those they represent are very effective here. So there really is not much to worry about because even if such a proposal would get as much as near any legislation all hell would break lose. Town halls would be full of their supporters. Just like in the past. The majority of americans does not want to bann them. The weapon industry doesn't want it. The majority of politicans - at the very least half of them, doesn't.
So in what even remotely realistic scenario would this ever happen?
The internet has one big thing and that is that the loudest and most screaching people are often heard. But they do not represent the actual and real political debate that's going on.