TK - I think there are two separate issues there. One is whether different norms allowed some people to get away with behaviour that was abusive even then (stories about hotel maids being groped by passing celebs, etc). The other - which is more difficult - is whether those norms were themselves abusive.

Take the relationship between a 15-year-old and a 26-year-old DJ: 30 or 40 years ago, I think we would have had a mixed reaction to that, ranging (on the male side) from "dirty old man" through to "lucky bastard", but there would have been a basic assumption that these things happen & it's nobody else's business. Now our attention is much more on the power dynamics involved - who's going to dump whom, who's more likely to get hurt, who's going to feel confused and ashamed at the end of it and who's going to think "job done" and look for the next one. And there's always the suspicion that the power imbalance is actually part of the attraction of a relationship like that, for at least some people.

That doesn't mean that all relationships of that kind are or were bad. But a lot are/were - and any that aren't have a very high risk of going bad, much more so than relationships between two adults.