Keep in mind that the underlying “what’s the matter with Kansas” thesis was built around questions asked / data gathered in the 1990s and the book was published in 2004, so things can (and will!) certainly change over time.
Morever, “Kansas” was always a proxy for a more general rural red-state America that still exists up and down much of the Great Plains. Check out Oklahoma, Missouri, Arkansas, and the Dakotas as examples of places that still hit many of the markers originally ascribed to Kansas in the book.
Again, this issue isn’t “Kansas” specifically, but the overall idea that a particular political group would vote in favor of particular values even when it seems to be against their own economic self-interest, and the fact that while who falls into that category has changed over time, the questioning of the motivation is constant, if still hypocritical. It just so happens that the book, when it was written, focused on Kansas.