Many companies tend to have geographically differentiated pricing to expand their market and make more money. Even if the prices aren’t completely matching the local currency equivalent (with respect to USD) and local conditions, they would have some compensation applied.
Apple has historically been against differentiated pricing, especially for its hardware. It also focuses heavily on retaining its 35% (approx.) profit margins. Only on a few services has Apple reduced pricing in the recent years in some countries (for example, in India, Apple Arcade, Apple TV+ and Apple Music are priced at nearly one fourth of the U.S. prices, but iCloud is priced the same as in the U.S.).
I’m not saying that all Apple hardware products are sold at the USD price plus local customs duties and taxes in other regions, but almost all of them are. What’s more ridiculous is that the prices don’t go down much even when Apple is assembling products locally and doesn’t have to pay as much in duties (a few iPhone models are assembled in India).
Since Apple has this business model, people in India who do know of someone coming from the U.S. or Dubai or another country/location where these are cheaper ask them to purchase those there and bring them down. There are several “Bring me this from there (BMTFT)” groups on social media to connect people.
For individual travelers the duty free limit (legal) plus duty evasion (not legal) in certain cases offer big incentives not to buy locally. I’m sure there’s plenty of organized smuggling also going on.
Whatever metrics Apple is tracking on sales by country get skewed by this, tilting heavily towards U.S. and other countries and making them seem larger than they are, while also making the countries with typically weaker currencies and higher duties seem as smaller markets than they are. (I know Apple can get country wise usage numbers from its telemetry in iOS, the App Store and other Apple apps)