Republicans are incapable of a long view. The reason Liberals stick together is they have a “cause” and a “movement”. Republicans are in it for themselves, their “loyalties” only to themselves and their fellow collaborators. Liberals will sacrifice for their cause. republicans won’t.
Also, liberals understand incrementalism as well. They have been slowly, patiently working on their cause for a century. Conservatives want a "perfect" candidate who will reverse it all in one election. Add to that the holly roller, church lady contingent who can't abide a "potty mouth", and the , "we are better than them, we can't sink to their level" crowd, and it's no mystery why we are in the state we are in.