Well, this is why Burma did the exact same thing (anybody who casts their memories back a few years might see how this relates to Egypt): >Naypyitaw, then, is the ultimate insurance against regime change, a masterpiece of urban planning designed to defeat any putative ‘colour revolution’ – not by tanks and water cannons, but by geometry and cartography. 320 kilometres to the south, Rangoon, with five million people,…
While skepticism is healthy, I'm not sure this is a fair comparison. > Mr Alabbar told the BBC, saying that the new development would sit on the edge of the existing city. They're talking about building something on the edge of the current capital. It's not like they're relocating to the middle of nowhere - the distance sounds more like Dallas/Ft. Worth or Minneapolis/St. Paul
Looking at a map of Kairo, this may be a similar approach, just that they build it next to the city (since they expect massive expansion in any case) instead of remodelling existing parts: whatever they will build will be more structured, and thus easier to lock down than the maze of the current city.