Yamamoto Yutaka (the director of “Kannagi”) gave an interview of Kaiyu magazine. Yamamoto said anime producers are running out of the novels and manga for anime adaptations taking “Toradora!” and “To Aru Majutsu no Index” for examples.
The anime of “Toradora” and “To Aru Majutsu no Index” were the final measure for the people in the light novel industry. There is no popular title left behind the two. But neither of them made a great success. Even Kannagi had been more popular than Toradora! for some while. I know it’s impolite to say this but the original light novels are not attractive anymore judging the fact that those titles couldn’t meet the expectations. We must regret that we had recklessly animated novels and manga one after another and relied on the popularity of the original works.
Source: Scan of Kaiyu