Mr Thierry
You seem to have quite a thing about Comair/Kulula/BA don't you. I think that Comair has to be the most successful airline in South Africa. It has very highly regarded safety, two very strong brands, and unlike other airlines in SA, MAKES A PROFIT.
Getting back to the original question with respect to retiring the JT8D powered MD82, I would guess that it is in part due to the fact that this represents good business sense in so far as the current and future cost of fuel is concerned.