the interior was literally falling apart because it was in the SLC area from new
Some cars also just don't weather the sun as well. My brother's Ford Fusion is the same year as my Cruze and has actually had way less sun exposure but it looks like it spent a few years on the surface of the sun. All the interior plastics have long since lost their finish and are pretty crispy. The rubbers too are pitted and have had chunks fall out. I have a picture somewhere of the steering wheel looking like the surface of the moon. Meanwhile, its exterior plastics are in great shape somehow. OEMs have gotten way better at sunproofing plastics but sometimes they'll cheap out.
I am continually shocked by how good the plastics on rusty cars are here in the PNW. I think you hit it when you said that it's how long cars stay nice, not just how long they stay functional.