Whether the fans think so or not, it's kind of true. Ninjago is close to beating Bionicle in it's life span, being currently in it's 9th year, and not showing any signs of stopping any time soon. It has a great TV Show that has arguably improved over time, and a pretty complex, yet easily accessible story. It was last year in LEGO's top 5 best selling themes. It has gathered in those years a pretty large fan-base, that may not be as big as the Bionicle one, yet big enough to potentially continue after the theme gets canceled.
Again, Ninjago can't even compare to Bionicle, but what has done so far deserves at least a little bit of praise in my opinion.