When I was a small child in the early 70's, I remember enclosed bins. However, that being said, there was rarely the stuffing of items into them as is done now. They seemed to be much smaller and people generally put coats and small bags up there (those awesome TWA/PanAm travel bags).

Also, I seem to recall 747's that had drop-down bins (versus the flip up door) and they seemed really fragile - not sturdy enough for today's rollaboards.