Part of the problem with the status quo with guns is that they are so plentiful in this country. There is so many guns in this country that any adult who wants one can get one. This includes any criminal, violently mentally ill person, or terrorist who wants one. Even if the gun manufacturers suddenly stopped, there is enough that it will not make a difference.
What can be done about it? Short of passing a Constitutional amendment, not much can be done in the short term. Sure, we can enhance background checks which will help but it will not solve the problem. When there are so many guns out there it is easy to find someone who is willing to “lose” as gun for some easy cash.
One can say it is a catch 22 situation.