(https://www.computerhistory.org/revolution/birth-of-the-computer/4/83)

early generation computers fueled a demand that was being supplied by rooms and rooms of human calculators calculating and checking each other's works for scientists, engineers, businesses, and government agencies

(Manhattan Project, Atomic Heritage Foundation picture)

they would not have died out, because they were a necessary part of the evolution of technology at their time. more importantly, they were more accurate than their human calculators. computers don't forget to carry a number to the next digit or flip them around. barring exceptionally rare cosmic radiation events. and their technological progression fueled an ever greater need until now when tech has entered post-scarcity when it comes to calculating power.

generative AI in contrast was an offering looking for a purpose. spare gigaflops no longer needed for tech people are trying to sell by building more and more hype for calculating power. sucks to be the one who invests into it, but that's business. sometimes investment don't work out. if microsoft can't hype up a demand then it is unnecessary technology.