There were several reasons why it became easier in the 60’s.
the #1 reason beyond all was the 5 day work week, without this becoming the norm most people would not be religious. This did occur in the 30’s but because of the depression and WW II its effects were not immediately seen.
Most Charedim will not credit the civil rights movement, but that was the second most important reason. Before the civil righs movement one could not easily state your rights. You could not declare you wanted Kosher food or not to work on Holidays nor could you state your inention to be differnet. When African Americans declared their civil rights others (including jews) were also able to declare their rights as well