Do discounting based on the purchase power parity of the visitor's country yield more sales?

Not everyone throughout the world gets their income in USD. A person's income also depends on the country he lives in. So a product that is very affordable by a US citizen may become very expensive for a citizen in India.

I see many online e-commerce stores sell digital goods like books, media, templates, fonts, digital greetings, etc. Such a business will not have shipping costs and also per unit production costs.

Do such business give discounts based on the purchase power parity of the visitor's country? If not, why?

I believe they can increase sales and thus get more profit just by making their products more affordable to their customers.