Yes, they are "property",
But seriously, I get what you're saying. But if Disney isn't smart enough to use their talent, you can't blame the talent for taking other opportunities. And you can't blame Nick for offering neglected actors work either. If Disney drops the ball, it's all on them.
in my opinion Samantha Boscarino is a star who got ripped off.
Well, that's sometimes just how it goes. But look at it this way, she went from a bit part in a throwaway teen movie, to a recurring role on a Disney show, to second credited on a Nick show. That's pretty damn good and a lot more than most. If she keeps this up she could have a full career as a character actor or go on to a lead role in a network show. She's only 17 afterall, she's got plenty of time.