Well, irrespective of your opinions re creationism and evolution in the formation of life, Darwininian natural selection certainly operates in the political sphere. If the GOP cannot or will not respond positively to the changing political climate, then it will die.
Of course, the problem is going to be deciding how to respond.
Check out the book The Big Sort by Bill Bishop. according to Bishop — and backed up by research — is that the dynamic that takes place when groups become isolated is one of increasing radicalism and inability to compromise. Those groups eventually implode.
Political groups across the spectrum on the internet are regularly purged to maintain that dynamic. If conservatives can’t buck that trend, then they’ll implode.