Is any direction in liberal thinking a dead-end?

In the previous post, I have compared the methodology of thinking in conservative and liberal minds. Conservatives are simple - anything you are trying to prove should pass a strict testing procedure. The level of difficulty depends on the importance of the proposed change in thinking but any increment is practically irreversible. This makes technical progress based on solid knowledge so fast - new knowledge piles up. 

Liberal ideas do not undergo any strict proofing - just compare liberal mainstream discussions today, five years ago, twenty years ago, and so on. Many previous ideas are forgotten and understanding of freedom wobbles as the earth's rotation axis. This makes me suggest that any liberal idea is a dead-end. In practice, I cannot support the current version of liberal thinking since it will change spontaneously when a new "thinker" of socialism, liberalism, libertarianism, ...ism appears. Since the new path to social happiness is unpredictable and the current one will fade away in the near future it is conservative to ignore all versions of liberalism as leading to a dead-end(s).  The most conservative approach to liberalism would be to consider it as an instrument of dominance rather than an ideology. This is a dangerous instrument easily sharpened by stones of real social injustice and ancient myths of heaven justice.