Comment by hibikir

Note that even many of those "long knowledge" things people learned are today obsolete, but people that follow them just haven't figured it out yet. See how many of those object oriented design patters just look very silly the minute you use immutable data structures, and have access to functional programming constructs in your language. And nowadays most do. Many seminal books on how to program in the early 2000s, especially those covering "pure" OO, look quite silly today.