Interesting how most of the press continues to be silent or completely not acknowledge these continued special election results that show Dems overperforming. Something is not clicking here with actual results and polling.
I think it's more that, except in certain high-income suburbs or some racially polarized rural areas, Republicans now have a base that turns out less than Democrats' base. In low turnout special elections in most areas, Democrats are overperforming.
It's not a coincidence that the one major special election since 2016 where Republicans overperformed was the highest profile one, GA-6 in 2017 (and also in the sort of area where turnout dynamics could still favor Republicans in off cycles).