I have a curious lack of emotional response to Prince's death, although I feel sad reading about friends' sadness (as expressed on their Facebook posts).
The last time I truly felt grief about a musician's death was when Michael Brecker passed in 2007. He also died in his fifties, and although dying that young always feels premature, he was still actively making music, and I felt that he was at his peak, especially with Wide Angles. I felt confident that he could go on making powerful jazz records had he lived longer.
I read in an obit that Prince made 39 albums, so obviously he was productive, but I can't say I paid him much attention since the 1999 days.