Goldwater did move to the left. He was against the rise of the Religious Right, supported gays in the military, and was pro-choice by the time of his death.
Actually, Goldwater's views were more or less consistent before, just issues such as you've named were not prominent back then.
Johnson, Carter, Clinton, Gore...
Southern Democrats move to the left when they become older.
Is this a rule?
It seems to be. LBJ would never have survived as Texas senator, had he been that liberal in the 1940s and 1950s.
As Senator LBJ was already more liberal than when he served in the House.
