Are mental illnesses incurable and lifelong?
No. When treated appropriately and early, many people recover fully and have no further episodes of illness.
For others, mental illness may recur throughout their lives and require ongoing treatment. This is the same as many physical illnesses, such as diabetes and heart disease. Like these other long-term health conditions, mental illness can be managed so that individuals live life to the fullest.
Although some people become disabled as a result of ongoing mental illness, many who experience even very major episodes of illness live full and productive lives.
http://www.health.gov.au/internet/publications/publishing.nsf/Content/mental-pubs-w-whatmen-toc~mental-pubs-w-whatmen-myth
you are talking like mental illness is incurable , it isn't.
But SOME don't. It's those for whom the possibility of assisted suicide MAY be the crutch that keeps them going.
I believe you've stated categorically that you don't hold with assisted suicide being allowed. I get that it's not something you'd want for yourself -although I WOULD ask if you've ever been in a place SO dark and for SO long that you may have wished for a way out- and even if it was legalized, it's not something which would be forced on you. WHY then, would you wish to force others to live, if, for them, living had become intolerable?
This isn't about "one size fits all". Each case is individual. It's not about "if I can put up with it why can't they". What it IS about is the need to walk a mile in someone else's shoes before we pontificate on how they should/shouldn't -my two least favourite words- live lives we have no understanding of.