Silk Road can be shut down, OpenBazaar is decentralized like Bitcoin so Governments cannot ban. OpenBazaar is not responsible for what is sold on it, just like how Verizon or AT&T are not responsible if their phone service is used for illegal activity. OpenBazaar doesn’t support anonymity, or fault tolerance from censors. That being said, someone can encrypt their entire OpenBazaar site and only give the decrypt keys to customers they really trust, thus making hidden/public stores that could function just like Silk Road once did. Worst case scenario, Darknet markets will fork OpenBazaar and run one for themselves, modifying it to run over TOR.