I suppose people like Tom Waits fit the criteria? Tom Waits can't sing. He is pretty good at telling stories but singer, puleeeeze.
If Rock or R&B were supposed to be the options where did all those others come from. Gene has come closer to listing people who can actually sing than most. Some of the choices others have made seem like the weird voice of the month. At least 75% of those "singers" won't be around 2 years from now.