Look at the West Coast.
I don't think that labor union presence has affected the Democratic vote very strongly here, but I may be wrong. At least in 2006 and 2008, labor was unimportant. While there are strong labor backgrounds of places like Oakland, Tacoma, Everett, Fresno, etc., Democrats have gotten plenty of support in the Silicon Valley, Seattle's suburbs, and Southern California. Whether or not this is enough, especially to deal with the rise of corporate power is questionable...
The East Coast is probably not in good shape. Progressivism and Social Liberalism that are powerful in the West seem uninspiring in the East. The Northeast will remain Democratic, but the Midwest, Pennsylvania, and other swingy areas are going to be difficult without labor groups.
The victories in Ohio and Wisconsin prove that labor is anything but dead. And Silicon Valley Democrats aren't real Democrats. Apple may love equal rights, but not in their sweatshops in China.