As the psychologist Philip Tetlock demonstrated in his magisterial analysis of 20-years of expert prediction, a dart-throwing chimpanzee was a better guide to the future.
In other words, you would have had a better chance of picking a top fund by literally throwing a dart at a dart board than picking a past top performer.
Unless an investor is just throwing a dart, many hours of analyzing individual companies, their products, management, competition, and prospects, are saved that can be put to better use in other areas of your investment planning and decisions.