In music production worldwide the 'Underground Techno' has a popularity that stretches its own definition, let along its style.
So, the answer to all these is co-existance and some people to stay true to their beliefs, keep Techno & Underground in perfect balance.
Then, the equation is legit.
Berlin is a city that had always been Techno, had always been Underground. Even when by the early nighties the rave scene became mainstream, Berliners went on seeking a darker, harder, industrial (that fits their environment better) scape. What they created they called it TEKKNO. And berlin stayed true to this character since.
This is a fact potrayed by Dj TANITH, his set was right to the core of Underground. Aimed precicely.