Yes, Democrats have outperformed prior voter turnout figures in recent special elections, but they’ve still lost 8 out of 10 Congressional special elections. This Blue Wave is primarily media-driven, not policy focused. Furthermore, the media and Democrats are reviled by a large segment of the population.
I think Pub turnout will end up being stronger than expected. The turnout will be driven by support for Trump not congressional Pubs. They've failed us too many times. Also, all the Rat talk about impeachment is going to make Pubs fearful of the radical leftists being in control.