This claim is wrong.
Marja' of Taqleed is a status of the highest knowledgeable Mujtahid, who can be from any country.
Today, you see in Najaf Ashraf four main Maraaje' of Taqleed , but no one asks about the country of birth of them because it has never been a criteria. Same in Qum and other places of Hawzas.
Wassalam.