Soul Train went into reruns because they ran out of new R&B/Soul they could dance to.
You can only play so much [[Music/Beyonce]] or hip-hop per show. Alternatively, they couldn't book any more guests after a while. Hell, they couldn't get people to show up for the award show. And them giving Ashanti a lifetime achievement award sealed its fate. Its cancellation was petty
The REAL reason it was cancelled was that people didn't want it surpassing American Bandstand.