a couple important points:
1) the number of professional programmers doubles every 5 years, so at any given time half of all pro developers have less than 5 years experience.
2) 1970 is the point at which brogrammers began to outnumber the first generation (who were largely serious engineers, & designed every worthwhile idea in CS).
3) most of that first generation retired around 1995.
this is why tech is like Scarfolk, collectively reliving the 70s every 5 years.