It's pretty difficult to tell why something didn't happen and while experts here try to hash it out, you might be interested in reading some previous threads on the spread of knowledge of the Vikings' travels:

• Did word of the New World discovered by Leif Ericson ever get to the Western Europeans? - 65 comments, over 1 year old.
• Here the commenters pull out sources from Germany and other areas to show the state of awareness in Europe of the New World before 1492.
• Did the rest of Europe know about the Vikings' discovery of America? - 8 comments, over 1 year old.
• This thread puts the above thread in context by summarizing how Scandinavian scholars did not realize that Vinland was a completely different continent.
• How did the Nordic countries react to the 1490-1500s New World discoveries? - 32 comments, over 1 year old.
• Users his talk about the internal politics and goals of the Scandinvian countries contemporaneous with Columbus's discovery and why they focused on nearer shores.
• Is there any evidence that Christopher Columbus (and other 15th century explorers) knew of Lief Erickson's travels and the Viking settlements in the New World? - 4 comments, over 1 year old.
• A flaired user gives a well sourced answer that explores Columbus's mindset and preconceptions that would have shaped his interpretation of the Vinland voyages.