That's the saying.
Think about it.
It isn't "survival of the fittest".
It's "culling of the least fit."
Just my 2¢.
Prove me wrong...
It is really neither.
It is who reproduced the most.
The young idiot who loved to pull the lions tail and got several girls pregnant before being eaten, his genes survived. The guy who invented the spear thrower but had no time for the young ladies, his genes didn't.