Mattel hasn’t had a lot of luck expanding their IP into live action movies–unlike Hasbro, despite having success with their Transformers movies, which aren’t very good–which probably has a lot to do with their characters not being very good.
Barbie? There’s an audience, but I am not sure how large it would be.
Masters of the Universe? There was already an attempt to produce a movie based on Mattel’s toy line in 1987.
It wasn’t terribly good–though had potential before they made their way earthside–but enjoyable in its own way (despite special effects by Richard Edlund and Frank Langella as Skeletor)
So enter Max Steel, based on another toy line from Mattel.