Will Buddhism last only 5,000 years after Buddha's Mahaparinirvana?

Is there any reference/citation saying that Buddhism or Buddha's teachings will last only 5,000 years after Buddha's Mahaparinirvana? How can this be possible if more people like to learn more about Buddha's teachings and Buddhism? Is there any weak point in Buddhism or Buddha's teachings that it is going to cease to accept and learn any more by people because that particular point is no longer adaptable by current/future generation? It could be related to moral principles, rules, disciplines, as well as concepts and ideas.