I agree. They are highly unlikely to fulfill their guarantees in any meaningful sense of the word.

My guess: it falls apart before even launching due to infighting, running out of funds, or political barriers.

Even if it gets off the ground, there's no way it'll be a self sustaining economy. Most likely it will import cheap labor from outside and attract people moving in who actually generate wealth from outside. In other words, just another community for rich people that isn't a self sustaining economy on its own.