If Alright With Me becomes the next single, all the 20,000 or so sales, so far, won't count towards it, right? As they're from the "album version."
No, all sales of the song will count. Also, for a second single, they don't necessarily release something else on iTunes. People can buy the album version if they want only the song. LLWD was released before the album, so they needed to release a single. For example, Light On was sold as a single, but Come Back to Me was not sold seperately from the album version. They can do something like this, though, for example, if they release remixes of the song, or B-sides. But, still, all the sales of the song count towards the sales of the single. Like, right now, whether people buy LLWD from the single or from the album doesn't matter. If they buy the song, it both counts for the sales.
Why buy an album when you can buy individula songs off the album?
I love that about iTunes actually. I admittedly buy more albums than singles in general, and I buy more albums than most people as well, but sometimes, you just want to buy Poker Face, not the whole Lady Gaga album. Which is what I did. So, I think, in my case, it's good for the artist, because there's no way I would've bought Lady Gaga's whole album. But, yeah, I'm probably not representative of the average music consumer at all.