Keep in mind that there are some species that are naturally going extinct and if it wasn't for zoos, they already would have.
Pandas, for example. Pandas just aren't mating enough. Apparently too lazy to get their freak on.
Well then I hope it doesn't bother you even more that there have been reports of findings of shark skeletons that match the size believed to be the megalodon, and these said skeletons aren't too old. The ocean is a mysterious and scary place, we don't truly know what's fully down there
*Mariana Trench, and it is unlikely that the Megaladon is hiding down there, it is too deep. Life that is found there evolved for that environment, adapted for the intense pressure and other environmental factors. A "shallower" water species wouldn't be able to adapt to it in order to "hide."
.
...but that doesn't nessasarily mean that it's not hiding somewhere else
Megalodons are much like great whites, with obvious differences, sea world has tried to capture and keep great whites but every time the shark would die. So the outcome for Megalodons would be pretty similar as well also this Shark is supposed to be bigger or as big or almost as big as a whale I don't think anyone would risk that.
Fun fact: SeaWorld never actually "capture and keeps" anything. Everything is either a rescue that is too injured to survive on its own if released, or was born in captivity and never learned the survival skills needed to live in the open ocean.
Well they might still exist because only like 3ish% of the ocean has been discovered. They might still be in the depths of the sea somewhere, but thats just what I think. :/
*Looks at the list of countless species humans have exterminated from the planet*
Zoos have done that to 99% animal species around the world, so why not to megalodon sharks?
Pandas, for example. Pandas just aren't mating enough. Apparently too lazy to get their freak on.
.
...but that doesn't nessasarily mean that it's not hiding somewhere else
no.