If the Republican Party were to narrow to only "true" conservatives, it would go the way of the Federalist, Whig, Know-nothing parties. Parties that focus on a small minority view only - are ineffectual and then go extinct.
Parties that create a clear core and common area of agreement and accept a range of views outside of that commonality grow, flourish, and become able to influence the government. This is how the Republican Party came into being from Free-soilers, Whigs, and abolitionists and how they came to be a significant party.
The result: look at the IL GOP
You're kidding right? Or are you just using George Ryan?