Sorry to sound so negative, but the closed ecosystem for this is a very bad fit for encouraging young people to code. They won't be able to share it amongst themselves, share to other devices such as smartphones etc. There clearly is a gap in the market and someone with enough resources could come up with an ecosystem that let's young people code in a simplified environment and share those results. in fact there's quite a few of such initiatives, it's just that they are lacking in terms of embracing many modern devices and latest trends such as sharing via github etc.