I don't think they'd bother with different modes. It's just that, like it is now, if you're a dev you can install iterm2 and xcode and lift the hood and bash a

I don't think they'd bother with different modes. It's just that, like it is now, if you're a dev you can install iterm2 and xcode and lift the hood and bash around, but if you're a consumer, you not only don't have to ever open the terminal, you don't even need to be aware it exists. This is why the hyperventilating about closing the OS is so overwrought: It doesn't need to be closed to serve Apple's purpose of having a walled garden, it just needs to be massively more convenient to stay in the walls of the garden if you're a consumer. Devs will find the gate and wander out on their own.