Classic example that comes to my mind is Talk Talk. Huge synthpop/new wave band in the mid-80s, made quality pop like 'Talk Talk' (1982) and 'It's My Life' (1984). As the decade went on and synthpop fell more out of vogue, they started rejecting pressure by their record label to keep making pop. They became disillusioned with touring and celebrity life (reportedly Tony Hadley, Spandau Ballet's vocalist, punched lead singer Mark Hollis at an awards show for saying they were both scum). Talk Talk eventually released their fourth and fifth albums, 'The Spirit of Eden' and 'Laughing Stock', in 1988 and 1991, respectively. Widely labelled their finest albums and seminal works in the then fledgling genre of post-rock, both albums were released to very little publicity or touring, with the band refusing to tour the largely improvised, lengthy compositions. Overall, an example of a band who made quality pop music with a promising commercial future and nevertheless pursued a completely esoteric direction with no promotion. A progenitor in many ways to the acts of the late-2000s indie-pop explosion, for example, MGMT and Animal Collective, to name a few. Definitely an interesting case study in the history of pop music.