I think you are missing the larger point about the republican party. At its core, it is truly a minority (meaning few members) party. In the minds of many, being conservative means being one of the “few people in the country who think that way.” The party as a whole seems ok with that. Its why they are so comfortable playing “lets all just get along politics” in Washington rather than being a true majority or opposition party. I think party elders would be happy to purge all the non-traditional members from the party even if it costs the party big losses in membership as well as losing the white house. I don’t think the GOPe is worried about the destruction of the party as you phrased it. I think the GOPe would look at it as a necessary culling of the non-maintstream republican voters.
“I think the GOPe would look at it as a necessary culling of the non-maintstream republican voters.”
which would mean “culling” over 50% of their current members if you look at the sum of the vote for Trump, Cruz and Carson, which equals the destruction of the party.