In fact, you are making stuff up without any proof or even any evidence.
There has never been a poll taken that showed that Gun Control, abortion rights, higher taxes or a weak foreign policy had a majority of Republican support.
All of our Presidential nominees that you mentioned CAMPAIGNED as “conservatives” (Heck, even Obama campaigned as a “conservative”)
Most people are not political junkies, and once you get passed the “litmus test” issues, voters decide if they like the candidate or not.
We need to do a better job of recruiting conservative candidates, and those candidates will then WIN most of the primaries, if those candidates do a better job of communicating with the voters.
The idea that we need a “3rd party” is insane, we will give the country over to the left, if we do that.
The idea that we can win elections by REDUCING our ranks is also insane.
To each his own.