Except that polling on Trump has been notoriously FAKE. I still believe that he has half the voters on his side.
You have to either be in the south, or located within a Trump stronghold surrounded by friends to have any confidence of publicly expressing support for Trump, whether it's a rally or just a pollster asking you a question over the phone. However, the fact that the MSM is still using tired old tactics like polling and focus groups in this information war should be heartening.
To draw an analogy, it's like attempting to mount a horse mounted cavalry charge in WWI. Oh, wait, both sides did try this initially until the lessons of cannon and machine guns were driven home. Thereafter, troops where dispersed along lines, becoming of course, the trenches of the Western front.
Back to the present day, the 10s of millions of people on the 'net represent the dispersed troops. They are required - for only one day - to expose themselves to enemy 'fire' when they go to vote (if they don't use mail in ballots). Otherwise, they keep opinions to themselves and mark the day they can take effective action via the ballot box.
I believe that DNC management is well aware of this trend. After all, they aren't stupid. Their job is to try and win (cheat) elections; there is no other way to power. The MSM can parrot this bullshite all day long, but until the DNC begins to focus on crafting some kind of workable coalition that reaches beyond ID politics, they are going to be lost for a very long time.