Social issues have been, and will continue to be, the death of the republican party because, for one thing, the social issue positions demanded by the social conservatives are, if viewed objectively, anathema to the principles of individual liberty and freedom that this country was founded on.
In point of fact, if it hadn't been for the social conservatives' fascist insistence on denying any recognition whatsoever to gay couples, the country wouldn't be dealing with the concept of gay "marriage" because there would have already been sufficiently robust civil partnership arrangements - available to everyone, and essentially what civil marriage is now - and wouldn't be facing the specter of having the government start forcing churches to recognize gay marriages.
You don't protect your house from a raging river by standing in front of it with a STOP sign. You protect your house by redirecting the river's flow. Social conservatives think they can sit athwart the current of culture and make it stop. They cannot, and as a result, their houses are in danger of being swept away.
To the extent that social conservatives want to fit society to their own Procrustean bed, they are merely a fun-house reflection of liberals.