Do toi think that other Nick's stars will hard to equalize the success of Big Time Rush in terms of music? Why?

Well, iCarly kinda already did. These are the 3 highest rated nickeloadeon shows currently in order:
1.) iCarly
2.) Big Time Rush
3.) Victorious

Yes, because I don't really think any other Nick stars can sing. They started out as actors, and they just got pulled into the musique biz to make plus money. Big Time Rush came as the complete package already. I don't think anyone else will have a successful musique career.