Disco is the first technology music. And what I mean is that 'disco' music is named after discs, because when technology grew to where they didn't need a band in the clubs, the DJ played it on a disc.
Electro is today's disco - making electronic music not for the sake of selling it but for sharing it and touring around the world D.J.-ing.
The music industry isn't converging toward dance music. Dance music is dance music. It's been around since disco - and way before disco. But there's different versions of dance music.