If you re-read my comment carefully, you will find that I am presenting another anecdotal counterexample, so I don't see where your coming from with that comment.
Also, we can discuss, but we should be aware that we can draw little to no conclusions.
That's a remarkable jump, to make that claim based on some rough assessment of a single person.
I didn't have duolingo but I still outperformed most of my colleagues who were in extracurricular English. What can I conclude from that?