Believe it or not, some dealers also do care about their customer's satisfaction of stuff they get. I don't mean dealers selling pills on raves where they can always find a lot of clients and as I wrote somewhere, many people don't care anymore that they actually buy pills with piperazine shit. They knowingly accept that and sometimes even consider it to be good. I've heard one amphetamine addict stating "those mephedrones and stuff from shops are even better..." (yeah, because one gets more mind-fuck from them and some people are interested exactly in it). Anyway, think if you sell high purity MDMA and have some regular clients, you don't want to lose them.
The last pill I took was from a good source and it was MDA-like but it was a few years ago. If I ever wanted some MDx(x), pills wouldn't be a thing I'd be looking for (I like taking MDMA with MDA sometimes - who can guarantee this? Nobody unless I can get pure MDMA and MDA).
I don't care about some MDx(x) prodrugs. It can save people's lives - you don't say... It's up to them if they want to take garbage like mephedrone and we all know it's going to be worse and worse.