I disagree with your assessment that Republican voters are primarily motivated by social issues, yet implicitly opposed to "pro-business and anti-labor" things.

I disagree with your assessment that Republican voters are primarily motivated by social issues, yet implicitly opposed to "pro-business and anti-labor" things. There are quite a few Republican voters who prefer them on (stated) economic issues and hold their nose when it comes to the social stuff. Really, the problem (or benefit, depending on your point of view) is that the two party system creates very broad coalitions of people with differing interests. The problem with the Republican coalition is that many of its constituents want things which are contradictory. Like, say, free market economic policies and stricter immigration (which is a form of labor market regulation). The Democrats have their own versions of these problems, but they're usually less obvious because their coalition is more explicitly transactional.