Someday I hope to have enough to make a throne-like chair out of Megalodon teeth, sort of like the GoT throne made of iron swords.
Think of it this way. Megaladon existed for ~20 million years. If one died in this area every year, you would have 5.6 billion teeth
Due to their shape and density, they were also more likely to quickly sink into sediment and avoid decomposition entirely. Then when the Pacific plate interacted with the North American plate, all of that ocean sediment was lifted up to form California.
They're actually relatively uncommon on the west coast compared to the East coast (the Carolinas especially). Sharktooth hill has lots more fossils of seals, sea lions, turtles, birds, whales, and other marine life.
I guess it must have been named because even a smaller number of shark teeth is less common than those other fossils in the area?
I think miscellaneous shark teeth are the most common fossil at Sharktooth Hill, they're just not as big or interesting as the megalodon teeth because they're difficult for a layman to age. Most megalodon teeth are obvious due to their size and most people are happy with a 5-25 Mya estimate.