They don't think so. They think their movement is over. You're right, though, there is no conservative philosopher of the stature of any of their major ones. One problem in perception is that any philosopher must at least mention Marx, and in so doing is branded, and the other is that to be credentialed one must establish one's credentials within the system--which is still dominated by you-know-who.
Allow me to disagree with you. I'll take Adam Smith over Marx any day... Capitalism has beaten and will always beat communism and socialism. I say this very confidently because Smith understood human nature better than Marx. Smith lets humans thrive, Marx suppresses them.
"To each according to their need and from each according to their abilities" is not how humans are made. Regardless how idealistic it sounds it will never produce anything but misery.
More recently we also have Ayn Rand, von Mises, and other conservative philosophers that have expanded on Smith's foundations.