Yeah no that's not what's happening. There is no petroleum to lose. Yes they are sometimes petroleum based but nothing is being loss. Once it's cured it's done. UV rays degrade everything. That's a fact. That's all that is happening. And yes "oxidation" is the correct term.
Your method will work. (little secret, Armor All is so much easier and will last a lot longer.) But it's just a bandaid. In reality, even though it looks "good?", it's doing more damage. It's not correcting the issue and will never feel or look as good as doing it properly.