You think they're replacing those bolts on race motors? No. There's not much, if any, force pulling on that pulley bolt. Similar concept behind wrist retaining pins.
And, I never said aftermarket was bad. I made my point; since you even contradicted yourself(point being the OEMs are far from crap). OE applications are designed with a specific stretch in mind. Assuming they actually cut cost where ever they can, you'd see a lot more of the same bolts on the car(buying bulk of a single item is much cheaper than buying different size/material).
The crank bolt is torqued at a much higher level than the cam pulley bolt(same with the flywheel bolt; items directly connected to the crank are also prone to much higher vibrations). And, I know the socket cap screws are more prone to rust because I have used them too! Specifically on the seat in the car, where the bolt developed surface rust just from humidity.