The King of France wanted their money, so made up some garbage about them worshipping Baphomet.
Some did indeed get away: after all they weren't all in France at the time.
There are well attested Templar sites in Ethopia and (amazingly) the North American continent - including a beacon tower with measurements based upon the scottish rood (sorry can't remember where it is exactly)
Interestingly the Templars made their money by beginning a form of long range banking/credit transfer - establishing lines of credit for crusaders.
Yeah my "wiped out" was perhaps an exagerration. The leaders were executed, not every last one. But the Templars as a functioning large-scale organization with the power they had was gone.