What do you think an insect's skeleton is made of?
But answer my question. How does protein decompose in the absence of moisture, light and air? Show me your research.
An insect’s shell contains silicates that make it harder than the blood proteins that were in the bone.
Your assumption of absence of moisture or air are absurd. If you’re going to try to say that any part of the bone was fossilized, moisture and it’s accompaning air have to b e present. Ask your evo pals, and I’m sure that they will straighten you out on that.