Many companies just use time. Plane tickets are cheaper if you buy them earlier, and these days video games eventually go on sale. Pricing the different region

Many companies just use time. Plane tickets are cheaper if you buy them earlier, and these days video games eventually go on sale. Pricing the different regions differently also "leaves money on the table", as there are wealthy people everywhere. Ideally you'd extract the maximum people are willing to pay, regardless of location.