Something else to consider, Sarah, is the infrastructure that needs to accompany aircraft orders. You can see the mess Dubai is in because they have suddenly realised all the infrastructure the city needs as an afterthought.
Buying the aircraft is the EASY bit. Planning the resources (both human and structural) that support the aircraft is another. It takes years to train pilots, build airports etc. etc. I speak from the air traffic control side of things, and I can tell you that a continued lack of planning of infrastructure will lead to MAJOR PROBLEMS- the least of which will be parked aeroplanes.
As an example, the German ATS provider is struggling with growth in air traffic movements of 8.6%. We are experiencing growth of in excess of 21%. You can argue that if you are near capacity, and grow by 8% then you have problems. But capacity is a product of the infrastructure. Picture the SZH in the sky.