this doesn't have 'gateways', that's Ripple you're talking about.  It's not easy to shut down the authorities.  They can be run from a cell phone or any other kind of unreliable connection(even email is possible).  It doesn't require that anyone run a server, so you could authorize transactions from anywhere, even a mobile device.  Secondly you must shut down ALL the authorities- and there could be hundreds all in different countries with different connections.  It's quite resilient.

The fact is if you want some kind of asset with backing, there must be some kind of authority somewhere, because ultimately you need to be able to redeem those assets somehow.  This system offers the MOST flexibility for designing that authority.