I understand you frustration...I really do. However, I am not sure it's fair to blame XM for the prices charged by retailers. Once the product leaves XM's factory...distributors, retailers, and end users are free to charge whatever they want. In some instances, manufacturers do have the ability / leverage to control retail prices. One of my hobbies is photography, so I have a ton of Nikon equipment. Nikon has sufficient leverage that they can mandate a "manufacturer's suggested price" and any retailer that sells products for higher than the suggested price risks not being able to purchase additional Nikon products in the future. However, the only reason Nikon has that type of clout is because they are a multi-billion dollar conglomerate. XM is not a multi-billion dollar company, XM is a small start up company that lacks the clout held by a Nikon, Sony or Apple. XM has no real leverage at this point...they need distributors and they need retailers purchasing their product if they want to be a permanent player in the collectibles industry.
Also let's not forget, one of the main reasons XM products are so expensive is the fact their license with Marvel does not allow them to distribute directly to the states. That's not XM's fault...Marvel placed that restriction in the licensing agreement. Obviously this restricts the supply of product to collectors outside of XM's sales territory which in turn leads to increased demand and higher prices.
At the end of the day...we have a free market system in place based on supply and demand. If you like when the free market allows you to score a highly desired collectible at a "steal" or "great price", if you like it when the free market allows you to sell your own property for a maximum price, then you have to accept the fact that occasionally the free market does not work in your favor. There are going to be instances where rabid demand is going to lead to price points that may exceed your personal disposable income. Like it not, there will always be individuals that have more resources than others. As you mentioned, the "rich" are in a position to buy whatever they want while others need to be more selective in regards to what they buy. Is it fair?? It doesn't matter...it's simply the way it is.