Collector's Edition means "don't smash it, please!" But they don't get that. In my estimation, almost nobody cares about the "handling" part of shipping & handling anymore. Not just games, but in anything. There's so much stuff nowdays you can buy brand new with obvious damage to the packaging. The term "damaged goods" use to mean something. Would probably get written off and sold to some odd lot retailer. Not so anymore. Just put it on the shelf and sell it with a straight face.
Speaking as someone who works in verifying/compliance for a (non-gaming related) distributor, you'd be singing a different tune if you were the one who was scrapping hundreds of dollars in value just because a box got slightly torn, especially when many manufacturers cheap out on packaging and ship it damaged to you in the first place. Its infuriating having to scrap items that sell for upwards of 300 dollars just because there's a big rip down the box. For the stuff I sell, a lot of people don't even care about said box, it ends up on the curb come trash day or shops will buy them at discount, throw the box out and then sell the item at the exact same price anyway.
If the packaging is damaged, there's potential that the product might be. Why not wholesale it? Seems like a better idea than trashing it. I just don't think it should end up at normal retail from that point. I don't know anything about your business, but it seems like you should refuse doing business with companies that cost you money like that.
We pop em open and check for damage, product damage in my field is usually very, very obvious. I could write paragraphs about why no wholesaling can occur at my company, but I'll just say instead that its not possible to fit into our strategic planning. We sell some of the more valuable packaging damaged items at a discount, as said above, with that discount probably becoming pure profit for the shops- I don't think the end customer will ever even know it occured. One thing I'll say is that USPS does suck, they are rather infamous as the worst of the major shippers and until recently we refused to ship with them due to said suckage.
Assuming your Sonic got mail damaged, it should have been packed better. But don't be so sure, its more likely than you think that that big dent was there long before the mailman got his grubby paws on it. The smush could have easily came from shrinkwrap contraction, it could have been dropped in the distribution center, it could have banged against another pallet OR had another pallet stacked on top of it. Shippers love to do that last one to save space, even when you specifically pay them extra to not do it. It could even have been damaged overseas shortly after being built and then shipped over here facing inward in order for them to not have scrapped anything. Your game, which you paid extra for, might seem expensive to you but someone who isn't into games will just look at the base price- in which case it doesn't cost any more than, say, a microwave- and it won't receive any additional care.