Hiroko Tabuchi wrote in 2010 in the New York Times:

At age 36, Hello Kitty may be running out of product lives.

That is the fear of executives at the Sanrio Corporation, the Japanese company that created the cute, cartoonish white cat in 1974, and groomed her into a global marketing phenomenon worth $5 billion a year.

“We badly need something else,” said Yuko Yamaguchi, who has been Sanrio’s top Hello Kitty designer for most of its 36 years. “Characters take a long time to develop and introduce to different markets,” Ms. Yamaguchi said. “But Kitty has been so popular it’s overshadowed all our other efforts.”

Sanrio has many failed successors to Hello Kitty, including Spottie Dottie the dalmatian and Pandapple the baby panda.

Their 2 moderate successes were My Melody (a bunny!) and TuxedoSam (a penguin!).

And a competitor has a winning panda character:

Sanrio is also being usurped by smaller, nimbler rivals. The formerly little-known stationery maker San-X has scored two huge hits in Japan with its panda character, Tarepanda, and its bear, Rilakkuma — which has charged up the Character Databank charts, ranking fifth in the latest survey.

In the latest survey, released this month, Kitty ranked a distant third, behind the leader, Anpanman, a character that is based on a Japanese jam-filled pastry and is produced by Nippon Television. The second spot is still held by the venerable game and animation brand Pokémon, owned by Nintendo.

Hello Panda is not made by Sanrio. D'oh!