Dubai doesn't have oil. It's a business center, ba<x>sed on the flow of capital. As long as it has the resources to pay back its debt, there is every reason to pay back, no matter how large the debt is.
The flow of capital in Dubai created a country with over $30k per capita GDP, year over year. Will they endanger that by defaulting on $50k per head debt?
What is the present value of $30k per year, forever?