[lern_too_spel]

This comment is exactly the opposite of reality. 3.x was the most locked down Android ever. Its source was never released. Since then, AOSP has gotten strictly more functional with every release. The proprietary Google apps built on top have gotten wider distribution on the devices that have Android installed, but that doesn't make AOSP itself more locked down.

[digi_owl]

From a user perspective, Android has gotten more locked down. This in that while previously one could access the file system directly, now on has to go via a sub-system that can deny or hide access arbitrarily.

[lern_too_spel]

You're talking about a security issue where one app could read and write another app's data. That's like saying Android is locked down because you can't read another app's heap.