From here: I've worked with every one of these girls and have interviewed them and watched their careers from Day One. I was the first magazine editor to put Hilary Duff on a magazine cover, which directly led to quite a string of those. So I know whereof I speak when I say that as fascinating as this is (it can also be read as darkly slut-shaming, a #ruinedchildhood meme), it's really no different from what happens to most girls—they go from total innocence to not so much. (Granted, these images are exaggerated as they're all actresses and singers.)
But what's even more interesting to me about this clever image is the implied expectation that they would have stayed total innocents forever in the first place.
The Disney/performing aspect is probably responsible for making them old beyond their years—Miley and Hilary were having adult conversations, very adult, at 15, 16, and making business decisions you or I would feel torn about.