who will work in the capital they can't afford to live in?
Its a scheme to put the power of the military even more entrenched and intertwined with the private sector...
Mubarak had a great relationship with the elite business figures... Sisi less so. This project is essentially Sisi's legacy builder. He will get the powerful capitalists on his side. He will also be able to prevent a 2011-style revolt because this new administrative capital will be just another gated community. When Tahrir Square was taken, it is where a lot of government buildings are, and Mubarak was screwed.
Sisi has put pharaonic monuments and private security guards to ensure it cannot be filled with anti-government protesters ever again.
This project also ensures that.