Francis has a good point and a good question. This is something I've been thinking about off and on for the last decade. My view is that the last real scene-changing thing was jungle, and that was 1993 or thereabouts. Styles a-plenty since then, including all that trip-hop, happy hardcore, gazillion {*}step spinoffs of d&b, electrotrash er clash, 17 indistinguishable flavors of trance, speedhalfdubstepgarage, "new rave" (huh?), "minimal," "progressive" and so on. But nothing as broad as a true new genre like, you know, jazz, blues, rock'n'roll, soul/funk, reggae, disco, punk, house, techno, jungle and name-yer-own.
Each of the major genres was associated with new sonic space created by the electric guitar, multi-track recording, synthesizers, PCs, and so on, combined with a cultural cauldron like New Orleans in 1948, London in 1961 and 1988, Chicago in 1953 and 1984, New York in 1925, 1956 and 1976, San Francisco in 1965, Kingston in 1967, Jo'burg and Dakar and Kinshasa in 1970, the Bronx in 1977 and on and on. OK, I'm getting a little far afield here. But Francis has a good point and a good question. fh