There have been recent stories about the Democratic Party embracing the affluent, single, and childless metropolitan voting block as its new power base -- to replace working class white voters. My gut feel from years of politicking is that singles/childless people in the thrall of trendy pop culture aren't a reliable source of votes.
While they vaguely support big government as a safety net in lieu of families, a sizable percentage of them just aren't that heavily invested in the future. They are particularly prone to taking a pass on state and local elections. Not only is there less media coverage to draw their attention but it is far easier for such people to vote with their feet when the logical consequences of their liberal policies turn their upscale playground into a dystopia.
On the other hand many in this group also tend to consider pride themselves as being too sophisticated to vote for anyone solely on the basis of party affiliation. That means the party has to spend time and money to get information into their hands about low interest races, like state legislative candidates, county clerks, state insurance commissioners, judges, etc. Show me a neighborhood with a lot of single/childless voters and I'll show you a neighborhood with a large undervote down the ballot and below average turnout in non-presidential years.