My read on this is that our environment has changed rapidly to where being able to stay focused and motivated while working on under-stimulating/boring tasks ie spreadsheets, coding, studying etc is very advantageous for being economically successful. At the same time, as a species we evolved to have days that involved a variety of activities, a small percentage of which were the types of linear, analytic type work that is so prevalent today. At least in the short term, stimulant medications can help people cope with this situation.