Please consider that for many this is an illness/disease, and the sufferer is processing a warped or distorted mental view of things that happen. 99.99% of peers of a suicidal person in the exact same environmental conditions are "normal" and do not have the same bleak outlook.
These are those who are still suicidal despite all measures they should be fine and happy. Just like how some people in third world are "happy" despite measures that their life is terrible and they have been dealt terrible cards. This population of suicidal folks will not be "cured" by changing these simplistic environmental factors, but will likely require serious psychiatric/behavioral work by the person to get better/ perhaps with some phara or biological help too if there is a biological factor at play.
That being said, I would agree if there are mechanisms to get Large Swaths of people down a couple points, in aggregate, this has the potential for the greatest societal gains; and overall societal happiness is a good thing to improve; but increasing overall happiness is a different concept decoupled by a few dimensions from helping those at risk of suicide and where a large chunk of their points truly stems from illness/disease that you can't attribute to socioeconomical or environmental factors.
I agree for the most part. Having it very directly effect my life several years back with a parent (and a few others), here are some important things to understand.
Hindsight does allow you to see small indictors of the pending action. They will be seen by many but without seeing all it is not intervenable. This does not mean preventable but may give you a chance to intervene.
IMHO I don’t see it a disease but as a thought process with a correct ending for those involved for the most part. (If you don’t understand this you are likely not at risk). At some point that process has gone down the wrong path. To be fair some it is caused by illness and medication does help, other its logic gone wrong (amongst other contributing factors).
Prevention, watch for key factor (most times small little comments out of context at an odd moment). At these times a small friendly/helpful response will prevent an errant choice.
The second is talk about it after the fact as a heads up and eduction for others, as society tends to down play suicide as taboo. It is the dark secret.
Personally, I know of 4-5 that have happened to people I directly know some closely, others at a distance, however, the most common thing is those odd moments leading up to the events.
One other thing it is a choice (whether we agree with it or not is different) of the misguided individual, in some cases it is the right one in their eyes. These are the one with the least indicators and likely most successful.
For your own sanity remember this, accept it (in those instances) so that you, yourself does not follow down the same rabbit hole!