When you think of the context of the original Fairy Tales, an age of brutality, plagues, famine, huge infant mortality,etc, you'd be forgiven for wondering if anyone at all was happy even briefly. Yet that was the age that spawned the glory that was the Renaissance. There were problems, and people managed to overcome them- with courage, ingenuity and optimism. Look at Chartres Cathedral if you don't believe me http://www.cathedrale-chartres.org/en/,143.html
I wonder sometimes if 'living happily ever after' simply means what it says. I've seen a few people who've lived to 100 plus, and that is exactly what they seem to be doing- living happily; i.e, living life head-on and meeting challenges, learning, exploring, ...ever after.