Look up Olmstead, Vance. Many states sued in the last 18 years.
Personally, about a quarter century ago, my own brother was denied adequate mental health coverage by an insurance company. They instituted a one time psychiatric residential facility limit--for life. He was 4 years old and used that up right away. No longer would be covered at all after that. I've had to wait in waiting rooms, trying to help as families have been forced to call every sort of hotline imaginable so that a kid, who was going to imminently kill themselves, would be given a bed. The best part was, there's often no beds. I know families that have been urged, coerced even, to give up custody of their kids just so that kid could get relatively moderate amounts of mental health services. In my own state, we have seen 70% of my states judges admit that they have sentenced someone to prison just so that they can get treatment. In the last 5 years, my state's juvenile justice system see an increase of 26+% of its population having an SED. Almost 90% of my state's juvi population has a mental health disorder. Oh, and here's the kicker. We're serving less than 10% of the seriously mentally ill adults, per state records. Kids, no one knows, because suddenly we don't publicly report on those kids anymore. The numbers dropped off the face of the earth, except when they tell the feds, perhaps.
As for whether it had anything to do with Vegas, I am skeptical. However, I notice that gun owners go to mental health immediately, because they don't want to talk about guns. Liberals bring up mental health, because they want to scandalize gun owners. Neither are very interested in actually doing anything positive with mental health services.