What do you mean by 'ROM' or 'burnt'? Android is normally on flash storage. Even if a device does not get updates anymore, you could still replace it if the boot loader is unlocked (e.g. Cyanogenmod).
Of course, you know this, so I can only assume that you are using such words for dramatic effect ;).
I don't understand this comment? What hardware is the Dalvik and ART stuff wedded to?