The album bundles 10 or more tracks; the single is a one-off. Which means ‘cherry-picking,’ and far smaller per-consumer purchase bundles.
And, a very basic reason why the recording industry (and broader industry) is in such deep trouble. Blame Napster, blame the MP3, blame the internet, blame whomever you’d like, but here’s what the last ten years have looked like.
The following comparison is between paid a-la-carte singles – purchased on places like the iTunes Store, and every album format put together (CD, LP, and digital album download). The data comes from the RIAA – first for units, then revenue on those units.