While Apple will spend billions on the latest techniques to ensure your iPhone can only run things Apple signed, there is meanwhile a real lack of enthusiasm around the basics like making the central messaging app not a native code shitshow invoking obscure (native of course) open source libraries they never update, you know, the basics. It's the latter that keeps getting their customers exploited.
Native code has more direct access to the system, e.g. accessing arbitrary regions of a process's memory via pointer arithmetic, invoking arbitrary syscalls, etc. In contrast, "managed code" like a JVM, CPython VM, etc. is subject to a more structured semantic model, which allows more restrictions to be imposed.
