The real inflection point was around 1975. A few years before that and there wasn't such a thing as a pocket calculator. A year earlier and a 5 function (the basics plus square root) was still $100 in 1974 currency. Then TI scientific calculators were around $200 or so. Within a couple of years even HPs were at around that price point.
In college (late 70s) I still took a slide rule to exams as a backup; LED calculators could run out of juice. But I never used it.