He was a very effective collaborator, who was able to popularise Avant-Garde themes. Nile Rogers talking about 'Let's Dance' to an audience of record producers is instructive.
https://www.youtube.com/watch?v=XaIx_FBk4-Q Essentially Bowie had an outline idea and session musicians fleshed it out. He always seemed to have the right musicians, Rick Wakeman for instance, here speaking about Life on Mars,
https://www.youtube.com/watch?v=QKSlJO51V7oI'm looking forward to the tribute concert, Nile Rogers and Rick Wakeman suggest themselves immediately, Elton John as well I suppose, Brian May?
I wasn't a fan as a teen, he had mainly female fans at our school, a sort of thinking girl's Marc Bolan, the musical components of Prog Rock were present, so we liked the music, but not the commercial aspect.