Except turnout doesn't really reflect that, there's symbolic value to voting which seems to spur participation by certain groups.
Anyway, it's a moot point, the electoral college is here to stay, it's time for the Democrats to get out of their rut and start broadening their appeal, Texas, Georgia, Florida and NC are there for the taking over the next couple election cycles. Take anyone of the four and a Republican can't be elected President. Montana may also come into play as it shifts from extractive industry to eco-tourism as its main economic driver.
Democrats need to dump the self-righteous tone and build bridges to flyover country states, sure, you're not going to turn Indiana or Kentucky, but Iowa is possible. Grab Georgia and NC, and SC might feel pressure to moderate or be left behind by industry location decisions. There's a clear path to a permanent Democratic majority, but only if the party stays in the center, if it moves left we'll end up with cyclical politics for the next couple decades (neither party garnering more than 40% and each election determined by how independents swing).
They also need to build their local party infrastructure, winning Presidential elections isn't as important as winning state legislatures (voting rules, gerrymandering) and governor seats (one source of viable Middle America candidates). Build from the bottom up and the nation will be yours. This process has started, in Georgia, in Texas, in NC, but they need to raise the funds, and recruit the locals nationwide instead of conceding large swathes of the country on a permanent basis, if only to have voices in the primary process that keep the party from swinging left.