Republican compromise is necessary to win the votes of the majority. As much as many of us would like to see a more idealistic republican party, it is simply not possible to achieve given the demographics of this country's voters.
You do remember Reagan, don't you? He compromised much less than Bush41 or Bush43, and won much more easily.
It is not only possible to win with less compromise, it's possible to win in a landslide or two!