He keeps going on and on about how historians would be laughed out of academia if they posited theories on how things may have happened. This is precisely what they do: just like biologists, they take physical evidence, compare it with previous discoveries and then hypothesise on what took place. Theories can and do change rapidly.
One good example is the significance of Bronze Age Mycenaean cult in Archaic (and later Classical) Greek religion. Well, originally, people like Nilsson said that Mycenaean cult was a direct precursor to Classical Greek cult. Then others showed problems with the theory and said there was no direct continuation. Now we're finding evidence that while there were breaks in tradition, some of them were less than fifty years and could easily be understood via oral tradition. So now we're coming back to a much modified hypothesis where Mycenaean cult DID have a direct influence on later Archaic and Classical cult, but it wasn't a direct continuation of ritual and beliefs, but the same sites, and similar rituals do show the lineage.
In fact, in some cases evolutionary biology has better physical evidence than some theories in archaeology. Something like the ritual and religious beliefs of the Etruscans (though we're making steady progress on that in terms of physical recovery). Hell, there are things about Alexander the Great and ancient Macedon that were only discovered in the past ten to fifteen years, which finally confirmed previous theories. (For instance the modern site of Vergina actually being the site of ancient Aegae.)