But the cost of buying and holding inventory goes up. If a store has 10k shoes in inventory @ $50/each, they are carrying $500,000 in inventory. If the shoes now cost $75, they need $250k more for inventory. Capital for inventory isn't free.
The need for inventory decreases at the same rate as the sales throughout, e.g. if it takes twice as long to sell a pair of shoes than you only need to hold half as many.