Everyone's all about high-definition video these days. Standard-def content? Pfft. Call me when you've got a resolution of at least 720p. And yet everyone short of picky audiophiles (who are just as likely to prefer lo-fi vinyl recordings) seems to be perfectly happy with 16-bit, CD-quality audio.
Perhaps the problem is simply a matter of supply. Higher quality 24-bit audio tracks have largely been limited to specialized media like Super Audio CDs and DVD-Audio discs. However, according to exec Jimmy Iovine, the Universal Music Group is talking with Apple and other music service providers about giving users access to 24-bit content.
Tested has a good rundown of the differences between 16- and 24-bit audio. The site suspects that the larger file sizes associated with 24-bit audio could tank its appeal for portable devices, although desktop users with capacious hard drives shouldn't feel much of a squeeze. Since music is typically recorded with 24 bits to start, there isn't a lot of extra work to be done on the publisher side.
Unless 24-bit tracks are offered at the same price as their 16-bit counterparts, I just don't see many users making the jump. The fact that so many people seem perfectly happy with their stock iPod earbuds tells me that fidelity isn't a priority for most. Even though I still buy my music on CD to avoid lossy compression, I'd have a hard time justifying paying more for 24-bit recordings. I'm much more likely to re-rip my entire collection and encode it with a lossless scheme like FLAC, which even with only 16 bits of resolution, still sounds fantastic on the sort of headphones and speakers most of us can actually afford.