So what might be the explanation of why and how the nameless NYC retailer might now be able to drop its Ektachrome price by $4 per roll? I am assuming in all of this that the OP is correct in stating that the drop in price is as stated, namely $4 per roll
The demand is both up and stabilized, and they are able to make the decision to increase their risk and place a bigger order with one of the potential wholesale suppliers. That supplier is, in turn, able to make the decision to increase their risk and agree to fulfill that order (and possibly orders from other retailers) by contracting to buy the film from Kodak Alaris.
Kodak Alaris is, in turn, able to make the decision to increase their risk and place a bigger order with Eastman Kodak to have the film manufactured.
Eastman Kodak is, in turn, able to make the decision to increase their risk and place a bigger order with the suppliers of the constituent chemicals necessary to have the film manufactured.
As the film is so new, and as the chemical constituent orders often take months to fill, at least some of these decisions happened months ago, and involved real risks, and real projections (aka guesses). In many cases, there were probably discussions with financial committees, accountants and bankers - with orders in hand, retailers, distributors, Kodak Alaris and Eastman Kodak all need to have credit in place in order to make the necessary financial commitments to fulfill the orders. Neither Eastman Kodak nor Kodak Alaris have enough capital to be able to ignore this latter issue.
In essence, this is a very new product, and the first batch(es) were almost speculative in nature. It is not hard to understand why the initial price would reflect uncertainty and low volumes.