A few years ago oneWorld round-the-world tickets were far less expensive if one bought one's ticket in, and departed from, Sri Lanka than from anywhere else in the world. Then it became Egypt. (I don't know where it is now, but it's probably someplace.) There were FT threads discussing travel agents in those places who would buy RTW tickets on behalf of Yanks and Europeans who would find a cheap flight or an award to Colombo or Cairo to begin their journey.
So: this ain't new, and it's all marketing. I don't pay the same for a Starbucks latte in Boston and London, either - even if I use the same Starbucks card, or the same app on the same phone, to pay for them. It's not a currency issue.