It would appear the real reason for the downturn in CD sales has been covered here - it costs too much to buy a lot of cr*p. Why do so many artists release an album, and then release 5 singles off it - usually with "remixes" of the same songs. Too many artists now producing one good song, and that's it. Who wants a whole CD of mediocre filler?
The record companies should be seeing opportunities here - why not join the bandwagon (no pun intended) and offer "official" downloads at reasonable price & quality?