Very cool find,
@Red Leg. I am not a paleontologist, but I believe the "official" explanation is that the megafauna died, therefore the Clovis people stopped making large points that were very difficult to craft and very heavy, thus they adapted to typical mammals and that is why the large points are not found thereafter.
The problems with the "official" accounts are two fold in my opinion. 1.) It is all predicated on the ironclad collective opinion of "Clovis first" migration to the Americas via the Asian land bridge. That hypothesis has been destroyed by the findings of far more ancient footprints in White Sands, NM. 2.) It requires a farcical belief system that waves of Asian geniuses and morons came over to the new world in waves, or that they went from geniuses to morons once they found a place to live in the New World as evidenced by incredible genius (e.g. Olmec) and not-so smart (e.g. Taino) gaining or losing knowledge at break neck speed.
If you leave science and enter mythology, there are a few global myths that seem to appear in virtually every culture. 1.) A worldwide flood/catastrophe around 11,600 years ago, 2.) A group of people, usually 7 wise people that were very tall, visiting groups and depositing lost knowledge on them, then leaving.
Now leaving the mythology and going back to the science, we do see startling evidence to support the mythology, debunking Clovis first and the entire story of the Americas. Some of this evidence includes the fact that nearly un-contacted tribes of the Amazon share DNA with those from New Guinea, the discovery that bio-char in the soil and the types of trees/plants indicates that the Amazon was built by man, for man, etc.
In short, scientists are afraid to publish anything that doesn't conform to the group think of archeology and they are not even digging in the right strata to look for pre-Clovis evidence because why would they since its settled science?