Back to the Future used Sports Almanac to cater to the average no skills Joe off the street watching a fun movie. Here on HN most people have something much more valuable in their heads already, technical knowledge. 1979? I code rudimentary VisiCalc, or dBase, or WordStar, or even all in one competitor in couple of weeks and build a $10 million company in a year. There are hundreds of similar essential business ideas to be realized in the past.