Brittle plastic

I have a friend who is a Materials Science Technologist and specializes in injection molded plastics. So... basically the same thing that's in computer cases (even though he doesn't deal with computer cases). I grilled him at length on this topic, and he insisted that the brittleness with age (and UV light) is expected and irreversible. Basically, the plastic softeners are off-gassing, and there's no way to put them back in. I'm still hoping for a happier second opinion, though I'm not holding my breath. In my experience, brittleness varies wildly and goes from "no big deal" to "crumbles if you blow at it", even for otherwise identical machines. I recently acquired a Japanese Ultra 1 clone, and the back was smashed in shipping, and crumbled into a thousand pieces not even large enough to glue back together. Luckily the front only had a single crack that could be glued back together.