No idea where you're getting this from. The paleolithic was during an ice age full of big fatty game like sloths, mammoths, and so on. Some believe we hunted these animals to the point of extinction with a tiny population, which would imply a very high level, arguably unbelievably high, of consumption of meat. Even if we didn't hunt them to extinction we certainly did engage in relatively large scale hunting and consumption of vast quantities of them, which already largely falsifies your concept.

Meat only became more of a luxury in the agricultural age where we started squeezing more and more people into smaller and smaller regions which meant there was no longer enough to go around. So plebs got the carbs, and royalty got the protein. FWIW you can also see this in the groups that have ancient traditions dating back far into the past, like the various tribal groups in Russia, Mongolian nomads, etc. Meat, and many highly creative ways of preserving it [1], remain the majority of their diet. They probably don't date back to the paleo, but at least far back enough to falsify the claim that animal fats are even remotely novel.

[1] - https://www.rbth.com/russian-kitchen/334150-dish-kill-kopalk...