I think it's a bit of a stretch to be saying that Sci-fi writers were making accurate predictions of what would happen in the future and when. Heinlein doesn't write about space because he thought it would happen at a particular time, it's because it opened doors into interesting stories and new ways of thinking about things whilst relating back to what already exists. It's less about what is going to happen and more about what's interesting. Personally I think even today we struggle to write good stories with that cope with the existence of instant access to every other person on the planet and every fact known to man.