I'm really just puzzled by the whole "I'm loving it" thing. You just said the exact same thing that I've been trying to get across here the whole time: "I'm loving it" is an ordinary English expression that was evidently already used (at least) 16 years ago and has been used widely ever since. It is completely unremarkable now. The show "Friends" didn't have any significant role in popularizing the expression, which is what mags originally claimed and what I was arguing against. I'm sure you disagree with her claim, too.
"Could I be any more X?", on the other hand, is not an ordinary English expression, at least not in the form it was used on the show, with heavy stress on be and sort of a strange intonation. I don't think I've never come across anybody using it that way. Well, maybe it was already being used by someone before the show came on, I don't really care (I also never said anything to the contrary); the point I was trying to make is that either way, it didn't have much of an influence how people talk. Which, again, you actually seem to agree with and which is the exact opposite of what mags was saying.
Okay, back to the original topic.
That's crazy talk, because someone saying "I couldn't care less" does not feel very strongly about not caring at all; that person simply doesn't care and there's no great passion involved. How can you feel strongly about not caring?
Now we're actually getting somewhere. The heart of the matter is that both "I could care less" and "I couldn't care less" are idioms and as such, their meaning is non-compositional: Taken as factual statements, they're both ridiculous. Of course you could actually care less, not mentioning the issue at all would be a start. And I don't have to tell you that caring more would be easy enough as well, for example by having heated discussions about the topic on the internet.
Now I should mention at this point that I don't think a claim that idiom A is more "logical" than idiom B has any validity at all. In fact, the argument can usually be made in the opposite direction as well, which I was trying to do here in order to demonstrate how arbitrary this concept of something being "logical" (I will not use the word logic here. Not even in quotes) really is. Well, you didn't counter my argument at all. I know what people mean when they're saying they couldn't care less. If you want to argue that an idiom is "logical", from what I understand as someone who doesn't believe in the concept of "logicality" at all, you should explain that one can derive its meaning compositionally.
Saying "I couldn't care less" can be uttered in just as monotone a way as "I could care less."
You might have caught me here. The thing is that I hardly ever hear anyone ever say they couldn't care less, which is why it _always_ sound a little strange to me. So I don't really know how other people would say it. If I were to read it aloud, I'd definitely have to put the stress on couldn't (where else?). The stress patterns of both expressions are definitely different ("I could care less" being more in line with other expressions used to express indifference), and I still think that the hypothesis that this is contributing (subconsciously, of course) to "could care less" replacing "couldn't care less" is a plausible one.