Right-wing "libertarianism" is an unstable ideology because it rests on a set of assumptions rooted in 18th-century liberalism, which itself was rooted in idealism.
Eventually right-wing "libertarians" have to answer: what is the basis for my belief in private property rights?
This has a few outcomes:
1. biological essentialism, which usually leads to fascism
2. embrace of idealism, which usually leads to religious conservatism
3. rejection of right-wing ideas