Is the UAE's growth sustainable?

Locals (emirates) represent only 15% of the population and own the majority of the firms in the country. Expats represent 85% of the population and consist of occidentals who have the management jobs and of Asians/Indians/ pakistanians who work as construction workers, at the bottom of the social ladder.
Culturaly, I doupt that locals, which represent only 15% of the population, will be able to preserve the traditions and values of the country in the long run. Economically, I believe that the country will not be able to sustain its economic growth if it continues to rely on expats to provide know-how considering these expats need to leave the country when their work visa expires. Can an economy evolve if there is no corporate memory and no internally developed strength? Can a country really thrive on a comparative advantage that it purchases from abroad? I honestly do not think so. People and firms come here to take advantage of the country’s resources and tax regulations (no taxes). The economy heavily relies on expats whose life here is only temporary, which creates short sighted growth strategy. In order to grow in the long run, I feel like the country will have to be more open concerning the residency status of foreigners.
Furthermore, the government of Abu Dhabi seems to be trying to build a comparative advantage in tourism (etihad), medias (two four 24), environment (Mazdar), manufacturing and high tech (according to the Canadian ambassador). I get the impression that by trying to specialize in so many industries, they will simply spread too thin and not be able to build a consistent brand image of the emirate.