How this group became popular is a mystery

Back in the 90's it seemed that in music Blackstreet seemed to be popular but it wasn't until the album Another Level was released that the song Don't Leave Me became their biggest hit but if it wasn't for Teddy Riley Blackstreet wouldn't have been successful by appearing in so many soundtracks for movies. Another thing I cannot understand is how in the world German singer Sarah Connor sampled one of Blackstreet's songs for her song and when you listen to it it's really annoying with the Bill Withers sample throughout. I cannot figure how in the world Blackstreet managed to have few successes with their debut album but they became famous with the Another Level album