Well the whole article seemed silly after he said this:

"First of all, you can't use heap - not when you're in orbit. Why? Because quite simply, if you do use heap, and malloc returns null... what do you do? You can't ask the user for help"

This is the OOM problem and is highly dependent upon the kernel you are using. Not bringing the kernel into the discussion means that the discussion is just silly. There is not much of a point to putting the heap in the stack as you said, but hey like the author we are just getting some ideas out there without bringing up the kernel.