Thanks for the picture of the Marina 106 board. It's on hold now though. The company behind it have the money but they might not bother building anything now since they will not be able to sell anything until completion.
MolsonExport, the big difference is these are all residential towers. Shanghai might now build 10 supertalls at once but it does build 1000s of residential highrises every year. I worked it out some posts back but the total possible population inside these towers isn't that high.
The marina is the best area in Dubai for people without families and so is still occupied even if the general population drops. This is because prices have dropped and people who were living in worse areas have relocated. I would worry about those cheap areas becoming empty more than the marina. Also if the marina is only half full there would still be people around because of the density.
And no, Dubai certainly does not have wealth, maybe a lot of negative wealth but that's it.
Some private developers though are very wealthy, especially some headed by someone very rich.