Aretha franklinis the answer to this question. Aretha Franklin has earned this title a long time ago and people do not want to reclaim this throne even after her death. People will always think of her whenever this title is mentioned. Some may wonder why she has received this even if in their opinion, there were singers who were able to sing better than Aretha.
The answer is simple, she is able to sing with her whole soul. It will not be hard to understand the emotions that she tried to convey through each and every one of her songs. You simply need to listen to one of her songs to understand how soulful she can get.