“I couldn’t care less” makes a lot more sense than “I could care less” when someone wants to indicate that the subject at hand holds zero, zilch, nada interest for them, but it’s the latter expression that seems more popular.
In my mind this is due to one of two things: 1) the former expression is too logical and correct, and therefore too boring, to be used and so the idiomatic “I could care less” wins the day, or 2) the latter expression is sarcastic (maybe as a shortened form of “like I could care less”) and that phrase beats the other because sarcasm is, as everyone knows, the highest form of self-expression.
Because one’s tone implies the sarcasm, “I could care less” is fine in speech, but works less well in writing (especially in journalistic reporting, where, unfortunately, the term crops up a lot more than it should).
As to those writers who use that expression without worrying about if it makes sense or not, I wonder: could they care less about their work?
