Even those paid-for newspapers, magazines, and newsletters had advertising in them. The subscription cost still didn't reflect the full economic value the publisher was capturing per reader. So in that sense, we still weren't fully paying for content even in those times.

And one thing with online subscriptions is that people, once subscribed, expect all other forms of compensation to disappear (ads, analytics/metadata-derived revenue, etc). So the publisher either needs the subscription to be high enough to reflect the full economic value of the reader (something that didn't even happen before) or still contain secondary revenue sources somehow or another but in a way that's subtle or hidden enough for paid subscribers to not complain about them.