Survival of the fittest isn't a Darwin line. That came later and people really messed up what natural selection is about thanks to it.
Nature isn't trying to find the 'strongest, best' creature. It simply asks this question "Can you figure out a way to survive?" If yes then you're in. If not, you die out. This is why you can have creatures that are absolutely weaker than others yet still flourish, because they found a niche to survive in. Many animals better than the Sloth are going extinct because they have lost their niche while the Sloth remains steady (well most of them, a few species not so well :/)
In any case, I'm not sure if HS decks really work under such things, because 'survival' isn't just based on niche or strength but popularity. There's many decks that CAN survive in the meta but no one wants to play it so it doesn't see play.
I prefer the adoption curve in regards to HS decks. Decks get created by innovators, then early adopters change it, then the majority find it and follow suit (the dreaded 'netdeckers!!!!!') until everyone is using it.
Ahh okay, thx for correcting me. And for the input