There is little evidence that Humans will adapt to a post SHTF scenario without prior preparation. Learning the skills to survive takes a long time. We are no different to the other animals on this planet. If a animal raised in captivity is released in to the wild without having learnt the necessary skills it won't last long.
Little evidence, except all of human history.
Your talking about specialist predators, or animals that require behaviors to be taught. No other dog taught my dog to scavenge carcasses, or hunt rabbits. He's an ace at both.
Humans are like pigs. Release a pig into the wild, you get a wild pig, not a dead pig. And real quick, you get packs of wild pigs.
Are you a Bushcrafter? I associate that sense of superiority over the rest of "untrained" humanity with bushcrafting.
Can't rub two sticks together and make a fire? Your dead.
It's not a vast intellectual leap for the average human to understand that **** just went South, and it's getting cold, and I need some blankets and lighters and food.
People don't just lay down and croak. Some might, but the "die off"? That's going to be from people who don't want to die making other people die so they don't have to. It's not going to be from lack of skills. Scavenging requires little in the way of skills. Murder? Brick, walk quiet, thump.
Being prepared doesn't make us smarter, or more "woke", or more dangerous, or anything but a bit less inconvenienced at the beginning of SHTF.
Those who say urban areas will be a complete mess post SHTF, I agree. But ethnic neighborhoods still exist, the tribe still exists, and a lot of those folks will get their **** in one bag real quick.