Update : February 29, 2020
In our younger days, Opal was a decent car. But, when one calls someone “Opal” (or “O Pei”), then one is “obsolete” (good to be ignored for getting old).
There is T.O. (Technical Obsolescence). Some artifacts can be found only in museums, antique fairs, and die-hard collectors.
Some technologies are disruptive.
Many automobile workers lost their jobs when robotics (and the related fields) gradually displaced them. Those, who did not have alternate skills, were hit hard.
Touch typists and secretaries found that their skills have been marginalized by the word processors, voice-activated systems and similar advanced tools.
I might not have a reasonably good memory and a hobby of “connecting the dots” of seemingly diverse topics if I had access to the wonderful world of Internet, AI, and Gaming.
Slates, Chalk & Talk, Logarithm tables, Slide rules, Multiplication tables (up to 16), Grammar books, Pronouncing Dictionaries, and most now hard-to-find artifacts trained us “remember” (not rote learning per se, but using visualization and tricks).
T.O. required me to unlearn some old skills, and to learn new “latest and the greatest” skills.