that's because of the cambrian explosion of what being a "programmer" means today. there's no time to learn all the history anymore. at the start of the PC era it was possible to understand every microprocessor architecture on the market and how to program them and programming languages for PC applications were sparse (assembly was pretty much the only viable choice although some profitable applications were written in Pascal). i may be off base here but i think 40 years ago the majority of programmers knew 80-90% of the history and you just can't do that today unless your career is "historian".