I think there is a big difference between scalpers and ebay sellers. Scalping tickets has become a big dollar industry, not necessarily the guy standing out in front of the stadium, but if you look in the paper you can see a whole slew of different companies that are in the scalping business. There are a limited amount of tickets for sale for each event and when a company throws a ton of money at buying alot of tickets they can really corner the market on tickets for this event. Thus if an event sells out because a ticket scalping company bought a good percentage of the tickets, they can charge whatever they want. They are, in effect, creating a demand by buying the supply. Venues and concert artists see this happening and decide to raise the ticket prices so the ticket companies can't buy as many tickets for an event, leaving more for the average Joe. Unfortunately, now the average Joe must pay twice the price for a ticket.
MR is different. In Oscale it is common for manufactruers to take preoders (not sure if this is the same in HO and N). If you pre-buy an item that you want from a manufacturer before it is made, you will get that item. That is why they take preorders, they can adjust their run based on market demand. This is how it is different from scalping. If one resale company decides to put in an order for 5,000 UP flat cars (in an attempt to corner the market), Atlas just makes 10,000 cars. Concert and sport venues do not have this option (some artists will add a second and third date).
Now after a product is not in production anymore the market value for that piece may go up or down but the manufacturer does not have much to gain or lose from this. If the value goes down they know never to make another run of these, if the value goes up high enough then it may make sense to make another run. However, the MR market is too vast for one (or many) resale companies to make a signifigant difference in the price we pay for in production trains.
If you really want something, buy it when it is in production. Then you are almost guaranteed to pay MSRP. If not, the free market of ebay will take over.
Check out the Deming Sub by clicking on the pics: