Ann: EdenCrete - US Update, page-37

Its difficult to make cheap carbon nano tubules and then make a solution of them which will evenly distribute in the concrete mix and be very strongly attached to the cement. Only Eden has solved how to do this in a convenient way.

Others have tried and failed, although from time to time sceptics appear in these threads claiming to be able to do it for half the cost in their own back yards, or suggesting that the company's claims are fraudulent or there isn't a market for it and so on and so forth... . However, they can't, they aren't, and there is.