The simple answer is: Republicans don’t know how to govern. They certainly don’t know anything about the politics of reform.
This is understandable. For most of the 20th century, Democrats were on offense. Republicans were on defense. The job for the Democrats was to pass legislation. The task for Republicans was to stop them. Both parties got very good at their respective roles.
But when we got to the end of the 20th centuryin this country and all over the worldthe need was to dismantle the failing institutions the left had created. That meant privatization, deregulation and replacing command and control policies with individual choice and free markets.
Republicans had no experience doing this.
All the successful conservative reforms of the modern era have involved Democrats. Jimmy Carter championed deregulationthe airlines, transportation, communication, etc.and brags about it to this day. Bill Clinton championed welfare reform and it’s been highly successful. Ronald Reagan’s tax reform was embodied in the Kemp/Roth bill. The Democrat’s Bradley/Gephardt bill was virtually the same and tax reform in 1986 was a bipartisan effort.
But when Republicans try to enact reforms on their ownwithout any Democratic helpthey are not very good at it. In fact neither party has been very good at switching roles.