How did the Puritans die out?

Puritan philosophy never really died out; one could argue that institutions founded during their time, such as Harvard and Yale, continue to promote some elements of their philosophy established in the early 1600's.  In terms of religious belief, the Congregationalists are the direct descendants of Puritan theology.  In terms of politics, as the ruling group in colonial New England, Puritan authority remained supreme until about 1700, when the Salem Witch Trials destroyed the theocracy, which, along with increased immigration of non-Puritans who did not adhere to their religious beliefs, weakened Puritan influences.   The governmental system established after the Witch Trials was more democratic; and became more so up to and beyond the American Revolution.  However, even early on, Puritans relied on town meetings as a form of direct democracy;  their establishment of even a limited democracy which became stronger and widespread as the country expanded is perhaps their most important gift to us.