I never tried MDA so my view of possible reasons for it not being available might be totally missed but that's why you guys are here to correct me in that case. I think at big industrial scale masterminds or better mastercash behind it long ago concluded it's not as profitable as MDMA. It lasts longer so less chance of people taking redose, and if taken than not as many times as with MDMA. It wouldn't be wise to make very strong pills yet cuz of significant cross-tolerance neither weak one are good option. Also as one friend of mine pointed how MDMA is a drug that's used in waves, like being really popular some time and than most but HC users get enough of it. I would expect that more intense, more trippy experience would cause more people to take longer breaks from it and take that breaks sooner. And possibly most important is that most xtc users don't want trippy experience at all as otherwise drugs like 2c-b would gain much more popularity.