Is it worth spending so much on mental healthcare?

I'm not a psychologist, nor do I have any expertise on mental health beyond a general interest in reading about it. That said, I have issues with statements like "expand mental health."

The obvious push back which we should all be wondering is, how exactly do we do that? And at what cost? Of all the medical advancements we've had-and some of them really are up there with truly revolutionary- mental health just comes across as one of those things that will never really be resolved, but we continue to dump obscene amounts of money into it. It's true, healthcare is already pretty expensive (whether directly or indirectly) but what happens when mental healthcare starts commanding hundreds of dollars per hour, subsidized none other by the state. What if you need repeat visits, like everyday, every month? It seems like a losing battle with horrendous cost, and no positive outcome at the end of it.

My feeling is that people who don't consider the opportunity cost and economics of such a scenario deny that this is the situation we're headed towards. It's another thing the repuglicans use as a way to deter from gun control. At the same time, I think both groups of advocates are just opening a can of worms. No one, including myself, is denying that we need to have real solutions for mental health, or that such a thing is a real problem. What I am against, are the misinformed and often mal-prescribed solutions that are offered to no real economic benefit, and the consequences of which society at large are going to have to bear more and more of.

So here's my question: What if some people, just can't be helped? What if spending resources on helping them with their mental health is just a dead-end. Its taboo to raise the question because people assume that you're against, or simply don't believe that people have real mental health issues. That's not what I'm getting here, and I don't side with that rationale. It simply scares me to no end that nobody seems to be concerned about the economic and social benefit to ever increasing spending on such things with little to show for it.