It's an ever increasing, educated, experienced group that believe that. It's a difficult one because it's incredibly subjective, however the sample size is large enough. It's something that needs some additional study but without people like Shulgin around, who's bothering?
The magic may well have a shelf life, the evidence here seems to be that we're all reporting the loss of magic and we all get nostalgic about the past... it appears to everyone concerned that we're burnt out - and new users can't tell the difference because they don't know any better.
There are however people in the middle here, I introduced many friends to MDMA around 2011. There was some decent stuff floating about then and we had some awesome times, but they were able to to tell the difference clear as day between good MDMA and this mongy mess that seems popular now. These aren't long term users, these aren't abusers of the drug (once every few months) and furthermore they've taken significantly less amounts of the drug compared to when I started.
MDMA (racemic) is obviously MDMA, but there must be more to it than that which we're unable to explain with any conviction (impurities, precursors, synth methods etc.)