It's not a date it's a vector space. Look at the velocity of cultural change along the dimensions of music, art, architecture, infrastructure, agriculture, rel

It's not a date it's a vector space. Look at the velocity of cultural change along the dimensions of music, art, architecture, infrastructure, agriculture, religion, ideology, politics, economics, technology (mechanical and informational) and so forth. 1940s to 1980s you see tremendous velocity on nearly every dimension. 1980s to 2020s you have tremendous change on IT, minimal change on mechanics and either stagnation or decline on most other dimensions. Especially physical manifestations are stagnant or declining. Of course you are going to find outliers, exceptions and overlap because this isn't a discrete space , it's more of a stochastic system with noisy observations.