I think it's a combination of laziness/avoidance of the work necessary and fear of failure. Once you are in a comfortable (though not great) place where if you stick it out you know you'll have enough (though never an excess) it's probably harder than you think to put yourself out there and take that risk. Not everybody has that gambling mentality, the members of this forum notwithstanding. When you are older with bills and people depending on you risks become that much more scary. What if you get sick? What if things go poorly? It brings to mind wacki's
thread, although I doubt most chances at taking risks could have such truly dire consequences.