If it comes to time when "dirty bitcoins" will no longer be allowed to use for storage or transactions, active freefloat circulating bitcoins will be very smaller than 21 millions of bitcoins. If this drop does not relate to regulations to seize bitcoins, censor transactions, Bitcoin price will soar to the Moon. Sorry for using Moonish word here.

Unfortunately, a scenario in which these things happen will be with massive severe centralized, censored, regulated world against Bitcoin, Bitcoin price will not soar, but will fall a lot.