You’ve obviously never seen the solid evidence of prehistoric man using the wheel that can be found in the comic strip B.C. I defy you to find more compelling evidence!
According to Wikipedia, the wheel was invented in Mesopotamia around 4000 BC, with independent invention of it later in China and the Americas. By that time Mesopotamians lived in towns and villages.
As to what a caveman is, most people would probably equate them either with hairy, heavy-browed Neanderthals, who had been extinct for tens of thousands of years by then, although hominids seem to have occasionally lived in caves for millions of years and a few still do.
For a conclusive answer, the wheel was patented in 2001 by someone from Melbourne. Since he was a lawyer, he obviously lived in a swamp rather than a cave.
I have no idea what the law requires where you are, but in the UK, the Advertising Standards Authority regulates print ads like the one you mention, and their rules state that advertising must be “legal, decent, honest and truthful”.
In practice that prohibits false statements presented as fact that might reasonably be believed by their customers, and might influence their decision to purchase. In that way, you could claim that your fizzy drink is the most popular on the planet Vulcan or your burger was the one best enjoyed by cavemen (because the public should be expected to realise that is not “true”). But McDonalds couldn’t claim that eating their burgers increases your lifespan unless they could back it up with evidence.
So I don’t think the ad would be breaking any rules here.
*Ladies and gentlmen of the jury, I’m just a caveman."
“I fell on some ice and later got thawed out by some of your scientists.”
“Your world frightens and confuses me! Sometimes the honking horns of your traffic makes me want to get out of my BMW and run off to the hills or whatever. Sometimes when I get a message on my fax machine I wonder, Did little demons get inside and type it? I don’t know! My primitive mind can’t grasp these concepts.”
“But there is one thing I do know. When a car company infringes on my patent, for an obviously nonobvious invention, then I am entitled to no less than twenty million in compensatory damages and ten million in punitive damages.” *
US law is not all that different from UK law. Slogans like “The World’s Greatest Cheeseburger” are technically called “puffery” and are legal to use, because they are considered to be an opinion.
Verifiable facts, especially about health - eating our cheeseburgers controls colon cancer - on the other hand, must be backed by solid research, well, at least by some study done somewhere.
Exaggerated images are normally considered to be legal as well, which lets all those tv commercials off the hook.