I reckon the reasons will be simple , nothing to do with colour or any shit like that. Just reckon some of the black producers may just have lost a bit of passion for it or may even think they've taken their productions as far as they can for the moment. Just as some of the white boys will have lost their passion too.

For the likes of Ghetto techno , to me it must come to a point where you can't do much else about " Ass and titties" etc ( just my opinion and probably not very balanced as I don't listen to a lot of it, but I did buy a few Ghetto records a few years back ). Perhaps they are just biding their time until Techno swings back round to where they feel they are at with their music.

Also a lot of the black producers of Techno made MASSIVE names for themselves straight away and produced a few Classic tracks. This means that they will pretty much be busy all the time making DJ appearances and stuff , so if they aren't getting that "itch" to produce then they'll just keep earning the bucks through Club appearances.