From ccn.com:
Writing in a Tuesday note to clients, a group of Barclays analysts led by Joseph Abate argued that Bitcoin and other so-called asset bubbles chart a similar course to the spread of infectious diseases, which plateaus once the population reaches the immunity threshold.

From the note:

“As more of the population become asset holders, the share of the population available to become new buyers — the potential ‘host’ population — falls, while the share of the population that are potential sellers (‘recoveries’) increases. Eventually, this leads to a plateauing of prices, and progressively, as random shocks to the larger supply population push up the ratio of sellers to buyers, prices begin to fall. That induces speculative selling pressure as price declines are projected forward exponentially.”