All based on supply and demand. Here is another example using the very one you gave. Thomas Jefferson Comm fetches around $30-40 on ebay. Right? Even better, the RFK half dollar with a mintage of 200k for both options still fetches the same. Ok, now the American Buffalo Silver Dollar with a mintage of 500k on both options can't be found for less than $150. Doesn't make sense right? How can a coin with a mintage of less than half the mintage of the Buffalo commem be worth a fraction of its value? Easy..... Supply and demand. More people are looking for the buffalo commem than the Jefferson or JFK which make them harder to get, which therefore drives the price up. And as long as us collectors continue to pay that money, the price will always stay the same or even possibly increase. At this point, it is still too early to predict what will happen with the Lincoln coin. With 500k mintage on all options, could end up like the buffalo commem or like the Jefferson commem. Only time and demand will determine that.
Remember all the hype with the Franklin Commem's? There was a flurry of buying at the mint web site, so much so, that I was forced to use the phone lines to order. Initially the aftermarket for these coins was in the $60-$70 range. Take a look at e-bay right now and you can pick one up in OGP for between $40-$50. It is my belief that dealers bought "heavy" into this issue with the hopes of strong demand. That demand was never realized, hence, a price reduction regardless of mintage figures.
NO, Date is TBD. My pediction is: Coin will be cheaper in after-market. Exactly like 95% of all comm. The Lincoln Comm. with the four pennies. That is another story. I predict a sellout and a price increase in the aftermarket.