The Katana is sort of a underground fad thing, just like Ninja's (which I believe don't actually use katana's), mainstream America is more attached to it Baseball and Corvettes and 44 magnums and Harley Davidsons. Of course we don't get many movies about Corvette driving on the edge police detectives with 44 magnums, oh wait yes we do.
Besides this year might of had a lot of movies with Japanese Katanas in them but next year looks to be the year of the Anicient Greeks. Sort of like the year we got all the deep sea monster movies, the Year of the Abyss, or how about the year of the volcanos, or year of the astroids.................