Haves and have notes is a divide that has existed for nearly the entirety of human history. It's not usually what people are referring to when they talk about the extent of the American divide currently. It's really more in reference to the fact that republicans and democrats rarely cross the aisle to support something that the other side is supporting. In this sense, the American divide has gotten wider because it's much rarer to find a republican and democrat willing to agree on something than it was in the past.
Here's a pretty interesting visualization that better explains the idea: https://journals.plos.org/plosone/article/figure?id=10.1371/...