Bush was elected as a conservative, even if of only the 'compassionate' type.
He governed as a big spending liberal. So, I think you have it quite wrong on who abandoned whom.
Your view of 'lead the nation as a whole', sounds a lot more like the 'finger in the wind' kind of leadership than the kind of principled leadership conservatives expect.
The Bush Tax Cuts, wrongly called “tax cuts for the rich” even by McCain, mathematically made the tax code more progressive. By taking a goodly number of low earners off the rolls altogether the Bush Cuts helped build the “47 percent.”
The progressive ratcheting is all but impossible to reverse. But if we went back to the Clinton tax tables it would do that. Oh the horror.