Do you mean no successful lawsuits?
Lawsuits have been filed.
http://www.cnn.com/2013/01/01/justice/connecticut-sandy-hook-lawsuit/
http://www.policymic.com/articles/21628/sandy-hook-lawsuit-damages-tbd-but-start-with-100-million
That was filed for google search hit... and that was quickly withdrawn btw....