2nd reply, because when I wrote my first one, your reply was just the first line.

For instance, the idea that early humanoids took the form of “cavemen” who ate a ton of meat is debated, and largely built on assumptions made from finding hunting tools.

I think they were highly seasonal. You had periods where you could gather a lot fruit and plants to eat, your hunting season and your "bare" season where you had to rely on surpluse and preservation. Diet would be highly variable depending on where and when and what resources and technologies were availbible.

The amount of meat eaten in the USA today is not historically common.

Not on average, for sure. But as I said in my first replies, there are examples of early communities that lived almost entirly of meat. Not even a side of fries.