Polarization at the state level is highly varied; some states (CO, TX) are polarizing rapidly, others are stable, and still others are even depolarizing (KS). If you put together all these contradictory trends (see the South, the West), the overall picture of polarization is dampened, even at the regional level, much less the national level.
Nevertheless, taking a long view over two decades, we can easily see how much the divide between Democrats and Republicans has grown. In 1996, even after the 1994 Republican tsunami which took out hordes of moderates, there were plenty of Republicans to the left of some Democrats as well as Democrats to the right of some Republicans.
Compare the states to Congress, seen in the plot below, where we also see increased polarization over 20 years. But Congress was already fairly polarized in 1996 with only a handful of overlapping party members. No more of that today.