There have been a lot of Hollywood people hit with similar allegations/arrested for them: Nicolas Cage, Seagal, Mickey Rourke, Christian Slater, James Caan, Josh Brolin, Terrence Howard, Billy Dee Williams, Eric Roberts, John Barrymore, Harry Morgan, ... The only one whose career really got hurt - some of these people were already going downhill when it happened - was Sasha Mitchell who lost his big Step by Step role. Which sucks, as he hit his wife to protect their kids.
Mel Gibson mainly has very good close friends like Robert Downey Jr and Jodie Foster who each have their own reasons to stand by him, but they haven't really managed to get him back in Hollywood.
Brown had huge hits again and is on a big world tour.
Mel Gibson, after dropping the n word, domestic abuse and going on a antisemitic rant against an officer, has still high profile advocates
http://www.neogaf.com/forum/showthread.php?t=1223232
Mel Gibson mainly has very good close friends like Robert Downey Jr and Jodie Foster who each have their own reasons to stand by him, but they haven't really managed to get him back in Hollywood.