I don’t think it’s impossible or anything, I just don’t think it would really result in anything particularly interesting. The best DJs often add such an obscure reference or song, dialogue from a movie, etc. that comes from their own individuality. Music recommendation systems seem to mostly operate on a tagging/descriptive basis, because obviously they don’t have real lives to draw these references from.

If an AI would make interesting DJ mixes that aren’t merely collections of similar music, I think they’d need to be constructed in a totally different way.