They have their blinders on and for most of them, seeing or hearing anything outside that narrow view is exquisitely painful, as only cognitive dissonance can be.
Hurricane Katrina provided the tipping point for a lot of them. Even Pox News was carrying the non response to massive human suffering among fellow Americans live and without a lot of propaganda to try to make the administration look less callous than it was. That woke up a lot of people to what a country with far less government would look like, indifferent to tragedy and both uninterested in and incapable of helping.
A few of the more reasonable people are still clinging to the party out of legacy, habit, fashion, or cultural identification..or even spite..but their number has dwindled. The party is largely composed of people who can handle only that tiny slice of the world that right wing media allow them. We now have the spectacle of the illiterate led around by a handful of rich men, but the illiterate are growing restive and want to take over.
2016 is going to be the watershed year for that party, the sink or swim year. Either the rich will assert control with an iron fist without the velvet glove and people will simply desert them or the bloodbath during the primary season will leave them unable to field a candidate and they'll go the way of the Federalist Party and the Whigs before them.
We are living in very interesting times, the Reagan coalition of the ultra rich and the super stupid showing every sign of breaking down at last, leaving them only the Nixon coalition of the rich and the bigots.
And that is no longer enough.
Capitalism is the extraordinary belief that the nastiest of men for the nastiest of motives will somehow work for the benefit of all. - John Maynard Keynes