Dej Loaf for one.
Azealia Banks could have very easily reached new heights for her popularity if she didn't shoot her career in the head based on her own stupidity.
Noname Gypsy and Tink are building a solid fanbase and both have popular connections.
Angel Haze had she used her growing popularity as a stepping stone instead of being a disappointment.
Justine Skye?
Def loaf is who I was referring to when I said "one off single success". Your list is a very short one and if we're being honest none of them are doing anything at a really significant level. Have any of those names even released an album? This is coming from a Tink fan btw, I'm not blaming the artist but the consumer.
Compare that to the early 2000's when we had Eve, Missy Elliott (women didn't have to be sex symbols), Aaliyah, Amerie, Tweet, Truth Hurts, Ashanti, India Arie, Macy Gray, Trina.
Something's off.