Sure you can, because you're talking about different inputs in your supply and demand scenario. You're also talking about different opportunity costs for the OEM, different incentives, and different outcomes. You're also assuming the person selling their Pixel is buying another Pixel, and not switching to a device made by a different OEM.

And ultimately, if buying it on the secondary market in such small numbers that it doesn't move the market, then it adequately addresses the concern.

Edit: I'm not saying there's zero effect of it, but it's likely statistically insignificant.