Sure, it’s possible for the Republican Party to turn into a sort of right wing of social democracy sort of party along the lines of the Christian Democrats in Europe, although that would mean rejecting everything they have ever stood for and leaving their donors – the rich and the corporations – politically homeless and without a voice.
The rich and corporations of Europe and in many other places have simply run up the white flag and taken what they could get, but the American version are ruthless, murderous, and do not shy from wickedness or the most devious trickery. I doubt if they will take this sitting down.
There’s also a very real possibility of a military coup in the US to prevent the establishment of any sort of social democracy. Most people don’t realize that the Pentagon has a class consciousness and the US officer class have class interests.
As we can see unfolding before our very eyes, if push comes to shove, the Republicans will simply become an authoritarian dictatorship to maintain corporate and wealthy rule into perpetuity.