Since we kinda started talking about rap, really the only rapper I listen to is G-Eazy. If you've never heard him, he's worth checking out.
As for mainstream music, I think a lot of the artists realize that what they are putting out is maybe not terribly high quality, but you have to respect their ability to recognize what is popular and what will be popular in order to replicate that and be successful. Plenty of people with amazing voices and no auto-tune will never be nearly as successful as the people you are referring to.