As not being an economist, I didn't understand most of the analysis. All I have is hope, they are correct with their calculations. Also, I don't see the reason people are arguing if the last year phenomena was bubble or not.  Would it change the perception of the quality of market or something? Besides the proof that it was a bubble (even if it has no weight for me) the paper has some interesting points. But as you said, probably that's not a big quality research