Going to repeat my post from yesterday, but the Hobbit movies have content from non-hobbit sources too, including LOTR appendices.
So the studio was probably better off calling the movies LOTR and using 'hobbit' in the tag line. Eg: Lord of the Rings - A hobbit's tale, Lord of the Rings - Desolation of Smaug, etc.
That could have retained a lot more of the LOTR audience.