I personally think it is cos ppl are becoming bored with other types of music and that there are many different forms of techno which makes them interested.
Uve got minimal, hard, acid and the more experimental stuff, so there is choice for all tastes.
The more dance minded ppl who have listened to other music but not techno are probably wondering why techno is still rolling along and changing, while their fav sound, for instance happy hardcore, is becoming stagnent and boring making them less interested.