It's not that there's not a single halfway decent artist now. There's a few. But it's just a few.

The negative effect of that mixture of the two genres is that alot of the knowledge how to make good R&B songs has gotten lost.

Pre-Hip-Hop Soul, R&B used to have sections (verse-chorus, AB, AAB, ABA, ABCBA, etc.) and was usually dynamic. This stuff today is mostly structured like Hip-Hop, usually with 2-bar loops, like a rap song. It's basically impossible to have alot of interesting harmonic ideas when you're using a two bar loop. The music also has no dynamics. And it's almost never danceable, which all R&B used to be, even the ballads.

I don't see this turning around any time soon either - the kids today seem to really like the stuff that's out now.