Suicide is very sad, and unfortunately extremely common these days. I have been affected by the loss of friends in this way and I think feeling unneeded is a huge factor, as you said very eloquently.
Another factor I can't ignore is the unhealthy habits of the people I know who have taken their own life - most of them alcoholics or addicts in some way, I feel that if they had known a clear path to get out of their addiction, with the understanding and un-judgemental support of others, they wouldn't have felt so lost of alone.
yes, they are just lost, they need people with angelic hearts to return them to the right path @calendulacraft