Those 732's adn Dc9's will be flying cirlces around the airbus for years to come. As for why they buy them? Well that is easy it's because they are cheap to buy. When Wardair bought the A310 airbus gave them the airplane for FREE for one year, not payments what so ever. Then when that year was up, airbus turnned up the heat and started to milk Wardair dry. Same goes with all the other airbuses, they are not designed to last for 30-35 years, they are cheap to buy, and very expensive to repair/maintaine, so the AI phylosophy is buy it cheap, when it breaks get rid of it and get another one. That is why the charters and upstarts like Rootsair like them, because it cost almost nothing to buy them, and in a 5-10 years when they start to break apart, you dump them for new ones. As for why AC bought airbus, well I don't have a clue, but I am sure that the kick-back scandle had some role in it.
"Clive Beddoe says he favours competition, but his actions do not support that idea." Robert Milton - CEO Air Canada