Like all fiction, it predicted a lot of things based on fantastic imagination rather than actual science, which should've been kind of obvious considering that there was no flux capacitor on a Delorean back in 1985 in real life. Not to mention that the future in BTTF changes every time Marty and Doc Brown go back or forwards in time. On a technical level, a lot of the technology in BTTF could've have been made today, much less in other sci-fi movies that had things like hoverboards or flying cars or even Nike shoes that velcro themselves as soon as you put them on {still don't know why anyone hasn't thought of that} but the reason why they haven't been made is because there has been little need to do so or demand for it, on a mass scale at least.
Plus they predicted that the Cubs would win the World Series in a 5 game sweep, that alone means that BTTF wasn't exactly the best predictor of future events, though you could say the same thing for most sci-fi movies.