The more popular shoes just sell out faster. Normally most styles will have limited availability on the market and newer designs replace old ones. Unfortunately, there are no sizes on order at all for the men's adidas Originals Freemont Mid shoe in either colorway currently showing on the website. It's possible a store may have more sizes left. But you would have to check with your local location to find out since store stock is separate from warehouse inventory.
Unfortunately, the warehouse will not be restocking any sizes for the men's adidas Originals Freemont Mid shoe in the University Red/University Red/Black colorway. This style will be sold out at the warehouse once inventory is gone.