[ryanjshaw]

The examples in that article do not actually argue for the point being made (that this has been going on for 70 years):

> His bearing towards male acquaintances, of whom he knew little or nothing and could care less, ...

Here, "could care less" refers to how little he knows about the male acquaintances, and is effectively saying he cares even less than the little he knows. When we see people write "could care less', they don't write it in the same context, at all.

And then:

> It is impossible that he could care less.

This is clearly a different way to write "couldn't care less", and is again not how we see people use the phrase "could care less".

That being said, "could care less" is definitely a thing of the last 10-20 years and is not going anywhere.