A psychological effect could be at play. If you pay $10 for a product and this causes the next person to pay $9 for it, it's an incentive against being the first to buy it. You would wait until others have bought it before buying. Or you might think the product is being priced unfairly and refuse to buy at all.

It seems that to counter this, you'd need another psychological effect to compensate. Like, for instance, offering the first set of buyers 'freebies' that actually have zero or near-zero cost (like 'the first 1000 people get to enter a prize-giving draw!')