A theory I've heard is that Neanderthals were actually modern man who happened to live several hundred years. As a result of the long lifespan and the diet they had, the bone above the brows and the jaws built up to form a sort of "flying buttress" of bone to assist in the chewing of the tough foods.
BTW--I agree with the date process. It's fatally flawed and doesn't give the correct date at all.
There are some problems with radiocarbon dating. The system assumes the percentage of radioactive carbon isotopes in the atmosphere is constant and this has recently been proved to be incorrect. Volcanic eruptions effect radiocarbon dating.
However, the basic PREMISE of the system is correct. We only need to make certain corrections to account for these discrepancies.
There are other problems which appeared in a recent study of the "Shroud of Turin". Apparently some material of organic origins like cloths and tapestries can acquire, over a long time frame, a heavy coating of bioplastic produced by organisms living on the original organic substrate, which can then skew the results to indicate a more recent dating. The solution is to remove the bioplastic before initiating the radiocarbon testing.
The studies I have read indicate ALL early hominid fossils demonstrate a very SHORT life span as well as numerous bone fractures and other kinds of skeletal damage which indicated a very dangerous, rough type of life. I never saw anything to indicate any early hominids lived for "hundreds" of years.