Two things tell me that is being done.
One, the latest conspiracy is that voter registration drives are run by the liberal elite. The evidence is, they setup their registration drives in heavily Democratic districts.
The other is, when I find someone not voting and ask them why, they say their vote doesn’t matter, that it’s all rigged. This was happening long before “fake news” became a thing.
I think people are pretty well informed on how many vote. Maybe fewer believe there are more Left-leaning people who are non-voters, but Obama proved you can motivate them. Then Trump found some others who he could motivate. I think that’s the answer, motivate voters. Well, that and fixing the gerrymandering and voter suppression, but again, that’s being done from the highest level.