Ummmm. The point of the article is that it did go to SCOTUS, and SCOTUS refused to hear it.
So, where do we stand?
Your'e right - my bad. I'm in a fog and, collectively, we're still in a legal fog.
I don't know all the details, but generally the Supremes only hear cases which in their discretion feel would offer some important policy statement or to clarify confusing or inconsistent interpretations of the law by lower courts. They need the case to be in the correct legal posture in order to do that. If there is a motion to dismiss under there are no factual circumstances which would allow the plaintiff to recover under the proposed legal theory, then the court will not want to hear it because it would not be a very clear preceden.
I would assume that if the case is tied, the losing party will appeal. At that juncture, there will be a factual record based upon the testimopny of witnesses, etc. and the court will be able to define the circumstances which forms the basis of its ruling.
Even though they might be rare, there are things gun manufacturer's might do (hypothetically) that could create liability. For example, if the company were condoning and particiipating in some illegal gun sale scheme, or thing such as that. It woulds like the Plaintiff's might be trying to allege some direct involvement that is clloser to the crime than I know. If they are not, I have a hard time believing that they will provide a set of facts that would make the court uphold a ruling against the gun manufacturers.
Any negligence case must include adequate proof of "proximate cause" between the conduct of the Defendent and the harm to the Plaintiff.
This case sounds as though it will be appealsed again after the trial, and there may be a dismissal of the case at that time.