I think you are seeing the effect of people who have decided for themselves to pursue lifelong learning. The Udacity/Coursera thing just clusters these people in a way that you notice them in the stats. But remember that statistics do lie. You need to dig into the reality behind the numbers, and question whether you are measuring all the right indicators.
My experience comes from several decades developing software and from time to time, hiring people. The people that worked out best, either as colleagues or hires, always seemed to be learning new things and were ahead of the curve trying out new techniques or tools before they became popular.
If you understand how a tool/technique becomes popular as the mass of software developers wrestle with new problems and finally find a way to master them, then it makes sense that constant learning makes some people stand out of the crowd. They happen to be the first ones to learn the new tool/technique and if they do not introduce it to their development team, then when management does make the decision to introduce it, the folks who know how to drive it have a chance to excel and appear to be rocket scientists.
My experience comes from several decades developing software and from time to time, hiring people. The people that worked out best, either as colleagues or hires, always seemed to be learning new things and were ahead of the curve trying out new techniques or tools before they became popular.
If you understand how a tool/technique becomes popular as the mass of software developers wrestle with new problems and finally find a way to master them, then it makes sense that constant learning makes some people stand out of the crowd. They happen to be the first ones to learn the new tool/technique and if they do not introduce it to their development team, then when management does make the decision to introduce it, the folks who know how to drive it have a chance to excel and appear to be rocket scientists.