The gun industry isn't a large source of income to America, so banning gun sales probably wouldn't make a dent in the economy. Also, recessions are caused by overinvestment in a single market, and that market crashes. Right now its the housing market. No one invests in the gun industry.
Yeah, their mindset won't change but they will comply. I mentioned Prohibition earlier. Bootlegging did increase, but mainly because the enforcement behind the law was extremely, extremely lax. And despite that, drinking did go down and many people did go sober.
The funny thing is, the crazies are determined enough that they will find a gun, somehow, some way. So whether you ban guns or not, crazies will still roam. Actually, that may not even be the case. Here's an interesting fact: two-thirds of all gun deaths are suicides. More interestingly, when a gun control law was passed, gun suicides crashed. Predictably. But here's the best part: suicides in general went down. The people committing suicide with a gun didn't go off and jump off a bridge. That simple deterrment saved lives, because like comitting a mass shooting, suicide is an impulsive act. Though it may not change the minds of every crazy out there, it will for some.
There is a counter argument here that argues that with a gun ban, people lose the right to self-defense, and therefore are helpless against lawbreakers with guns. Well, it doesn't work that way. Sticking a gun onto ordinary civilians doesn't do much good while under fire. The brain works in strange ways while under fire, and more often than not, an armed civilian is just as useful as an unarmed civilian.
I honestly don't think a gun ban isn't a bad idea. If it's allowed to last, people's mindsets will change. Whether that's a good thing, or it'll lead into a snowball effect with all sorts of things being banned, that's a different matter. But the thing is, there are so many unknowns, and in the current political environment, there is still a lack of support for gun control. Until the people's mindsets change, don't expect a gun ban anytime soon.