Jermaine doesn't have a voice to do rock, he basically has a R&B crooner voice. Other R&B singers during that time like Luther Vandross, Freddie Jackson, Alexander O'Neal, & Peabo Bryson didn't sing rock either. Their voices are not suitable for that. It's not like Luther could take Vince Neil's place in Motley Crue. In the 80s, R&B didn't cross over much, so it wasn't considered "pop". The ones that had big success on the mainstream Top 40 made obvious pop records that was less R&B based like Whitney Houston, Lionel Richie, & Billy Ocean, dance music like Jody Watley & Janet Jackson or Pat Benetar style pop rock like Tina Turner. Basically Jermaine didn't make it as big because he doesn't have an image. He's more a Johnny Mathis or Frank Sinatra as far as performance goes and that didn't fly in the MTV generation. He's not that interesting to watch, lol. That's why Jermaine had more success on the R&B charts than the pop charts. An image wasn't that important, at least as far as adult R&B went. Acts like Rene & Angela, Anita Baker, and Maze fit into that category. Besides, I don't think Jermaine had competent people working for him like Michael & Janet. The behind the scenes people like mangers and so on are very important. Let's face it Michael & Janet or other acts like Bon Jovi, The Police, or George Michael wouldn't have gotten anywhere if they had a Joe Jackson as their representation lol. Look at what happened with the Victory Tour with people like Joe, Chuck Sullivan, & Don King who didn't know what they were doing running things. Janet's 1st album doesn't sound any different than Shalamar's music (because it had their producers) and they were popular, but they didn't have Joe as a manager like Janet. When Janet fired Joe after the 2nd album she blew up.