Dubai will become a fascinating ghost town when oil is eventually replaced.
No, there are other very strong forces in play.
If you look you will see strong financial forces have set up there. Any global or regional company worth a damn has intensive presence in the form of offices or distribution warehouses or even production facilities. Industrial facilities using the feed stock are already old and mature and new one on the way.
They may well corner the aluminum market. The largest smelter in the world is there using the gas to turn the turbines to make the massive amounts of electricity required. They have world class ports and sell their port management services abroad.
The businessmen are in charge and they are diligently growing their businesses.