What better advertising than having a narrative where your product is "sold out" and in high demand, with media running stories about it ?
Especially when the "scarcity" problem can be addressed easily.
It can't be addressed quickly. Takes months to make more. Seems like having enough when folks are buying makes more sense, than a little free press and then maybe they'll still be interested in buying in a few months.
I repeatedly hear that something being limited in some way gets Japanese customers really excited. Supposedly that why you even see themed cafes that only pop up for a limited time.