Having seen all this from the inside of more offices than I can remember, I would say definitively yes. That programmers did have to introduce delays for that,

Having seen all this from the inside of more offices than I can remember, I would say definitively yes. That programmers did have to introduce delays for that, and for other reasons. However, this was a trust thing, and not an innate limitation of human capacity. Now that we’re in 2020, I would argue that almost 0 users need that crutch. If the work is done, it’s done. Similarly, employees on early keyboard-only terminals didn’t need any delay either. They trusted that when they said do X, the system did it. How else could you process dozens (or hundreds!) of items a minute?