Realistically, the contiguous states will probably have separated into a small number of self governing units and the US as a country won't exist. The deep south up to Virginia and west to Arizona will probably be sparsely populated due to the ravages of climate change, and the remaining areas will be split between being hyper protectionist against climate refugees and more culturally permissive like the western seaboard and north eastern states are today.

As for technology, we will likely have it in abundance and the benefits of this will more greatly favor those at the top end of the increased social stratification, while the great majority of the population live at or near the poverty line. For most, this would result in a greater focus on the immediate community due to a lack of mobility, and this would also lead to much less cultural blending and increased tension between communities and regions.