Playing with the idea of a Theory of everything, I thought "If something can happen, it does.".
This does not explain the origin of our world and it's not a TOE but a concept in that direction.
You could say "I can jump right now, but I don't" and I tell you "no you can't jump right now"! The notion of proving me wrong prevents you from jumping. Maybe physics and anatomy allows you to jump, but in this very moment, your mind stops you.
Maybe now you jump... okay... that's a psychological reversal which stopped your mind from blocking your jump, now it's really possible.
"We could feed the world, but we don't." Yeah, technically this is possible, but globals politic and the way capitalism works prevents this.
This house could collapse, why doesn't it? Simple. It "could", but it can't because it's stable. Maybe one day, if it's condition gets worse, it will.
Basically my idea means that everything will happen, if there's no counter-force. This also counts for the rise of systems like molecules, society, cities, solar systems and their collapse.
Thus fragile or stable only means "How much is preventing something from happening?"
Are there any examples of things that really can happen, but don't? This condition means that nothing prevents it from happening.