On point is that (real) techno is only available on Vinyl. But you can´t put a vinyl in your car stereo and you can´t play it on your pc while you work, you can´t listen to it on your discman while you jog... basically a vinyl is pretty useless unless you´re a dj.
Also there are many people who choose to listen to techno because it´s underground. If it wasn´t underground, techno would lose many followers to other underground music styles. For these people it´s not about the music, they just want to be different from others.
You all know what happened to trance: as soon as trance music started airing on mtv and started becoming "commercial", people started looking for something new, because suddenly they no longer identified with it.
Aside of that, another thing that happened to trance is sony: Sony and other big music industry giants suddenly sense there´s money to be made, and they´ll have their clon army of in-house producers make a bunch of crappy tracks, which´ll sell due to massive ad campaigns.
It´s what they´re doing with trance now. They´ve got an army of producers with multimillion dollar studios and basically all they do is cut original samples from 80s tracks and lay a trance beat under that. It´s cheap as hell, but they advertise it and they air it on tv and kids buy it. You don´t want that happening to techno.