You forgot to mention Hillary's unpopularity,the Comey effect along with the fact that many Dems gave Trump a chance based on his rhetoric - none of that will be in play in 2020. Dems will be motivated in 2020 unlike 2016 where many expected Hillary to win regardless of their vote, this time they have a target in Trump given how he has behaved in the WH.
Democrats need to move on from saying the 2016 election loss was all about Comey, the Russians, etc. -- stop trying to find excuses (which is a continual liberal problem) -- Man up and state clearly that changes are needed to the party and its message in order to have national level success in 2018 and 2020.