I agree, it's not just the economy. But neither is it religion because every religion and non-religion has a pro-life spin despite their philosophy and religious texts not really proving it. Ask a non-suicidal atheist and they will also vehemently disagree that non-belief is more pro-choice and pessimistic of life. In fact, over time as a Christian, ironically, I've realized that my religious texts are very negative about how THIS life and THIS world is (full of sin, evil, corruption and pain man causes etc.) and the hope is in a NEW resurrected afterlife rather than clinging to this passing world.
So to answer your question why humanity is generally anti-suicide or pro-life according to my religious belief, it's because God never created suffering and death. "Life is a gift" only made sense when life was originally created (to be immortal and without suffering). Death is the cessation of life. When Adam and Eve sinned though, death and pain was introduced to this universe. So since death was never intended, it feels UNnatural. And that explains survival instinct and why we on average cling to life no matter if painful and meaningless since it ends. When you think about it, survival instinct makes no sense when we know we all die anyway and eventually know the species dies as well. So being anti-suicide and pro-life is like a visceral trauma response. Bring up death to an average person and they will try to suppress it. Try to tell even a 65 year old that they will die soon (even 20 years more is not that much) and they will feel offended somehow as if they think they will never die). Ask children under a certain age and they actually think their grandparents will never die. Imagine how few animals even know they have an end (when they see a fellow species member die they must think it was killed and not aged and died "naturally"). Death is something even us highly conscious beings have suppressed to think about on a daily basis even though it's literally all around us.
Anyway that's my uncommon answer to this question.