EK is a company chasing profits and ever increasing margins. Much like any other company. They are able to do things differently due to the nature of the country/city where they operate, they are not bound by certain labor laws as most legacy carriers are, and are able to operate on lower costs at their hub as well... they have been able to grow significantly due to an ever expanding pool of travelers coming from the sub continent (and Africa), despite if the management might want to elaborate other segments. Their focus on premium passengers comes from the general ethos of the emirate/city to focus on luxury (which is not necessarily a bad thing). Other aspects that have come to play over the years are a general movement of economies in Asia and Africa.

Dubai was always a city of trade and transfer before it became famous for being famous(or infamous!), it naturally became the point of transit for accessing the region. EK was, is, and will continue to be the face of Dubai and its most profitable component. Dubai/UAE has also helped the growth of EK by making it increasingly easier by people from all countries access into the country - especially when it is the only option for a 'western/developed' nation experience for people living within a 5-6 hour flight radius...

Other hubs of business and transit in Asia: Singapore and Hong Kong aren't going away, and are certainly not shrinking violets with their eponymous carriers.