7. People like to complain about gerrymandering as the cause of Dem losses.
It just is not true. Dems have their votes concentrated in heavily Dem districts in urban areas. Reps have their's spread out. So you can have 3 districts where, for example, the Dems win 90-10 in one district, and Reps win 55-45 in the other two. The total vote is Dem 180 and Rep 120 but the Rs have two districts and the Ds one district.
In addition the Voting Rights Act require minority districts be maintained. This has caused Dem minority votes to be compacted in a few districts allowing Rep to have small majorities in surrounding districts. This is why the Rs always vote to maintain the VRA. It is just math not gerrymandering. No professional campaigners think gerrymandering is much of a problem especially since it goes both ways depending on the state.