Because the lowest wrung of Maslow's Hierarchy containing food, heat & shelter has become unobtainable to us.
Because the doomsdayers about global warming were right and no one listened until now when it's too late.
Because the difficulty in just taking care of ourselves has risen to the point that we haven't the energy or the willpower to take care of one another.
Because we look back on the time when our parents raised us and realise they had it better than us and that progress has given way to not just stagnation but now full on regression.
Take your pick.