To me Trey is good but he doesn't have IT. He sings about the same things. And although he has never made a pop song all his hits are about sex or if not about sex it's about drinking or something with a ft artist(see Say Ahh and Bottoms Up). That's why he can't keep R&B alive.

Usher can but Usher's problem is he has always been R&B then he decided to make pop music. He needs to stop that.

Chris was never really just R&B. I mean his first album kinda was but after that he was startting to do pop and that's before other male R&B artist did. Usher and Chris both do great R&B stuff and even Trey. Ne-yo to me will never be apart of keeping R&B alive he isn't that good anymore. Chris needs to hang up the auto-tune and his next album should be mostly R&B if not all. She Ain't You is R&B and does good on Pop radio so you don't really need a pop song for it to be great or crossover. I think R&B can be kept alive it's just everyone wants to experiment and try new things with this pop era going on and that would need to stop first.