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.
Why is "sharing to smartphones" in the set of things we want out of the technology stack that encourages young people to code?
Smartphones aren't the Nintendo Switch, and (for me, at least) wallpapering over the differences in hardware platforms is not an exciting part of the learning-to-code experience.
