I've questioned the wonder-working powers of high voter turnout before but, shockingly, not everyone has agreed. But here is some more evidence undercutting the more-turnout-will-solve-everything thesis from a massive study by the Knight Foundation. There's a great deal in their report, including a very interesting typology of nonvoters, both their characteristics and reasons for not voting, which suggest a complex phenomenon not reducible to voter suppression and/or insufficiently radical candidates.
But, regardless of motivation,what if all those nonvoters really did vote? Surely the Democrats would kick Trump's ass back to Mar-a-Lago for good. Sorry, it's not that simple, as the chart of key swing states below shows. Democrats would benefit some in the national popular vote but wouldn't be helped sufficiently in the Electoral College to take Trump out.
If this doesn't make you question the turnout mythology currently popular in Sanders wing of the Democratic party, I don't know what will.