I feel what you are saying and conveying ... but you lost me first at "didnt think he was that big" when he was battling michael jackson for top spot for years and throwing down instrument wise
and bragging about being able to do and create as he pleased. Purple Rain was gospel, Lets go Crazy was an pop anthem and When Doves Cry was a 80s Pop smash. None of that doesnt appeal to black audiences especially in the 80s. You mentioned Rainbow album and it still grossed 4 million as his worst performance. Dude was a performer so besides labels crying, I dont think he really gave a fukk about money situation... plus he could have dropped an album a year if he wanted.
people said he didnt fare well after hiphop and rap, mostly due to hardcore aspect... but realistically Prince got super weird around that time and then his marriage happened. He wasnt completely for that age group, plus lending MC Hammer is 2nd biggest hit and loaning his samples to 2pac and other smash hit artists... I wouldnt say he was overlooked at all. If you look from late 70s to all of the 80s ... then 90s where he got married in the middle and lent out hit songs in the beginning... 2000 rave joy album marked a comeback and perfect vibe for MTV ... to musicology (as you said the top tour of 2004) onward... he actually didnt have a particularly rough patch as we are led to believe. I just think he was a true artist in every sense of the word and didnt really think about money or how people felt. It's clear he did weirdo shyt alot of times purposely too, since he told his bandmates to dress the part and stay in character... that means he was cognizant of the image and vibe he was giving at all times. Then you have the story of him going into a depression when MJ passed and the stories of them talking alot on the phone. I think or 95% know that they must have talked a long time ago and decided to play their beef mysterious and let it roll for press. Personally dont think Prince was supposed to be on BAD at all like the story says... it doesnt even make sense really. If they were supposed to make a song together, surely two legendary musicians since children, would have created an original song from the ground up together. I dont even think Warner beef was that bad after the slave shyt... I think it became a talking point for other artists and promo too, because he always just gave advice and chilled after... and even when he started reclaiming his masters before he died.... he planned on staying and renegotiating with Warner too. To sum it all up, I think his versatility wasnt niche really... he just needed to show you, why he was here and who he was. Compared to most pop stars who only do copy and paste stuff to maintain their images. He was technically the most normal artist in that sense of being himself and creating.