You cant make that kind of comparison. A big mac costs a third in SA than it does in US. But we pay equally [this is called The Law of One Price - Purchasing Power Parity for the economists here].
The Cost of Living Index of Johannesburg is 109, Pretoria is 106, and Capetown is 91. Washington DC, which is extremely expensive compared to where I live, has a Cost of Living Index of 92. Besides, an international company like an airline does not set its fares based on local costs. Two like flights--length, time, day--are going to priced similarly unless there is significant competition on one of the routes. Getting a RT flight from Johannesburg to Madrid for under $500 is a steal and hardly suggestive of "very high costs" for SAs.
Perhaps word choice in your original post has colored the tone of some of the responses. By introducing yourself as a member of "one of the oldest (acknowledged) Catholic families in my country," you could be seen as thinking of yourself as somehow superior to others on the forum. Then, by suggesting that you will be one of the few Africans on the Camino "presumably due to the very high costs involved for us," you could be seen as placing yourself in an economic class superior to that of others on the forum. Next, by declaring that "finding 5 weeks of leave is very difficult for those of us who have jobs in the 'real' world," you could be seen as holding the rather naive opinion that all the others who walk for 5 weeks are trust fund babies or something similar, but we also have to figure out how to get that much time. Finally, and perhaps most significant is your parenthetical statement near the end of your post: "[I actually feel like having a very serious conversation with our
Apostolic Nuncio - the Pope's representative - over what can only be called
clumsy handling of this matter by the Archdiocese of Santiago]." You could be seen as declaring yourself powerful and important: you can speak to the Apostolic Nuncio! You could also be seen as extremely condescending by glossing "Apostolic Nuncio" so that the lesser, ignorant humans on the forum would be duly enlightened as to the meaning of the term. Food for thought before your next post.
By the way, the botafumeiro is not part of the mass anyway, as at least one other person has mentioned. Only after the mass has ended does the botafumeiro swing, and it is a chaotic, circus-like ending to what I think is supposed to be a meaningful and spiritual experience.