The GOP starts focusing on an election about 6 months out. The Democrats started the battle for 2020 on 11/7/18. Therein lies the problem. Political work ethic.
In my area Democrats won on every level beating Republican incumbents who sat on their hands. Almost all of the Democrats were first time, female candidates. Mostly Community Organizer types backed by every far left organization known to man. Millions of dollars came from out of state to fund constant TV ads, mailings, and door to door visits. I only had Democrats come to my house, and the vast majority of literature I received was Democrat.
Every representative I now have is Democrat on every level. State House, State Senate, Congress. Oh, I do have one Republican Senator, but that's it. Even our governor is a far left, progressive Democrat.