Why do you assume that Amazon don't know what they're doing here?
Although you returned the laptop, the annoying process might have discouraged many others from doing so. The shipping cost and the cost of processing the return are likely much smaller than you expect when accounted for on Amazon's scale. And by making you return and re-order, they are putting the risk on you if the laptop is not the identical product, rather than taking on the costs of administering a price drop refund themselves.
Of all the things that Amazon do, analysing the game theory of customer behavior so that they can do as well as possible out of interactions like this seems like one of their biggest strengths. They certainly have thousands of skilled people working on it.
As for return scams, I would not take what they say at face value. My opinion is that they have quite sophisticated models for analysing returns, both for detection (to distinguish between the behavior professional scammers and regular customers) and economically (to decide that it's cheaper to give the latter the benefit of the doubt, let them keep returned items, etc). The only flaw is if otherwise legitimate customers start to think they can get away with falsely returning 1 in 20 items or whatever. So they 'blather on' about return scams, not because they are material to their business, but to make it clear that if you cross an invisible line, they will go from not caring about your $120 air fryer that you ended up with two of, to pursuing serious legal and criminal consequences.