So only the rich can have guns?
Gun violence should be solved but it's a tricky situation with more guns than people in the US even if you ban the sale of all new firearms it would not decrease gun violence by much (it can even increase it at some point).
Also people can manufacture their own firearms in accordance to the rules and regulations set by the ATF.

The majority of gun violence in the US involves handguns, and it doesn't involve expensive handguns, the glocks, sig's and 3000$ custom made 1911's aren't used, what are used are still old throwaways and cheap ass 200$ guns.

Rifles are rarely very rarely used, and modern "sporting" rifles are pretty much a unicorn they are only used in such tragic events as the one were discussing here but these events are not even a rounding error in the total number of casualties of gun violence in the US.

Which is why the "anti-gun" lobby is losing the "war" they fight all the wrong battles, look at the assault weapons ban it was utterly useless none of these weapons were ever used in gun crime or at least were any substantial percentage out of it.

Banning a gun because it has a muzzle break or a front grip is just asinine because they have absolutly no effect on the nature of the gun, and those gun as said do not appear on statistics.
Then they went and banned guns by name like the "streetsweeper" which was a shotgun that not only that was never actually used in a crime in the US it was imported in extremely low numbers and was mechanically a faulty weapon - as it was utterly unreliable one would be hard pressed to fire a single drum magazine out of it (which contained iirc 10 rounds) without it jamming, it usually jamms on the 2nd or 3rd shots which often requires you to take out the magazine out completely.

It was banned because it looked cool, it appeared in late 80's hollywood movies and when some US company decided to import it from South Africa they gave it a "cool" name so the anti-gun lobby went after it, almost as if this was an intentional trap.

If the US is to do something about gun violence this has to be a multi layered approach attacking the heart of the problem from the crime especially in the impoverished black communities which are both the perpetrators and the victims of the majority of the violent crimes in the US.

Changing the public's opinion on gun rights and then doing the right thing and limiting it through a constitutional amendment as I am not fond of the idea of states "bypassing" the constitution, even if their intent is good it's not a good precedent.

But overall outside of rare incidents even in the US like this which is a mass shooting not related to criminal activity the gun violence in the US is part of a larger problem which is violent crime which is while it has been going down overall it actually has increased in some demographics, as ugly as it sounds if the violent crime rate which includes murder, armed robbery, assault etc. of the minority populations in the US would be the same as the white population it would decrease in virtually every major US city by about 90% bringing the total violent crime rate to rates similar in Europe and even lower than some EU member states.

So while going after guns might sound like a good idea, but in the long run it's futile, there are too many guns out there and it would not solve the underlying problem which is the violent crime rates in minority demographics in the US.
Mainly the black and hispanic community which has to be addressed but due to the obvious toxic nature of this topic no one really wants to touch it, you are automatically painted as a racist, apologists, or a combination of both depending on what argument you are trying to make.