I'm not sure poor mental health has that much to do with NHS underfunding tbh. Not for the Axis 2 disorders, which are perceived as psychological rather than organic in origin.
It's more that human beings are wholly bad at having it, maintaining and keeping it. We are pretty vile to each other a lot of the time, and even more vile to ourselves. Has anyone never stood in front of a mirror and hated something that they see? And then called themselves all kinds of insulting names, like fat, ugly, useless, worthless etc. Humans invent standards no one can meet then trash other humans when they fail. No amount of money will alter that, in fact sometimes it makes it worse. The change begins with us, each single individual. All MH professionals have is a toolkit they can share, they don't have the answer. Having more hammers won't build a better shed, but knowing how to use one will. Why don't we try and solve it by not making it 'everyone else's' problem - ie, I don't have to do anything because all that needs to happens is for the govt to give MH services more money...
Perhaps we could start by being a bit more pleasant to each other, less judgement and more tolerance perhaps?