If the price is not totally ludicrous then the scalpers outbid pretty much everyone else. If you know MSRP, then normal people bid MSRP whereas scalpers take a million dollar loan and bid all 10,000 units at double MSRP, then sell at triple/quadruple MSRP. If you don't know MSRP, then most people won't know how much to bid, and won't bid at all, leaving just scalpers.
Scalpers bid high because they know they can get when more. The people who pay more to scalpers on an auction side like eBay would just bid that directly to Valve
They wouldn't, because they wouldn't know how much to bid. People pay more on eBay because they see how much more they need to pay. The whole point of a Vickery auction is to eliminate this feedback. A tiny fraction of megawhales will overbid by an order of magnitude because they want the gadget at literally any cost - but the vast majority of people would underbid, specifically because scalpers haven't started selling it yet for inflated prices. The act of putting it on eBay itself increases how much people are willing to pay for it. The big winners would be scalpers, who, being both the professional appraisers and the market makers, are in the best position to bid well and are nearly guaranteed to resell at a higher price.
> If you know MSRP
Giving a list price would make no sense in the case of an auction, in fact would be misleading, (maybe even illegal ??), and not just because of these issues.
Most people would bid the maximum that they can justify. That's like saying that only scalpers take part in auctions (easy counter example : eBay).
If people were perfectly rational robots, this could work. Also, sales jobs wouldn't exist and politicians would be held accountable for their promises.
In real world, sales tactics work. People can be influenced to pay more than they thought they're willing to pay. Scalpers know this and exploit this at scale. A Vickery auction gives basically zero opportunity to get talked up. People will bid at the "thought they're willing" price, and scalpers will outbid them. Then the same people who underbid on auction will go to eBay, see it listed at "influenced to pay more" price, and buy it for much more than they bid.
And yes; the vast majority of eBay auction bidders are indeed scalpers, whose day job is to look for cheap deals that they can resell for more. It's extremely rare in this day and age to actually take advantage of eBay bidding to buy in-demand stuff on the cheap. It's much easier when there's "buy now" option but you need to be fast and lucky because you're competing against scalpers here too. Of course things are different for stuff that few people want in the first place - scalpers are not interested in those because they're too hard to offload, so you get your fair chance.