Hypocrisy didn't destroy Puritanism.
The decline of the Puritanism was not caused by the puritans' hypocrisy, but rather from themselves and outside sources. Even when the first Puritans settled in the New World, Puritanism was already declining in Europe because Puritans had different beliefs. Also, the flood of non-Puritan immigrants to New England was already downsizing the influence of Puritanism.