I think its just a natural schism in the republican "big tent", for a long time neolib con Republicans have been able to keep the more reactionary rightwing onboard by being seen as the only viable option for them, but with the rise of Trump and the increasing reach of far right media this far right side of the republican party sees that it doesn't need to kowtow to the neolib cons anymore to win and they can maybe even reverse the relationship.

Centre/Left wing parties have always tended to be more split in this way with vying for power between centrist neolibs and sucdems, this is the case in most western countries. It seems to me that the right in the US has just hit a point of alienation between their two main groups that they are now having similar issues to more left parties. Hopefully it will rip them apart but time will tell.