The best example that Bitcoin is well designed and decentralized was seen a few weeks ago. When the Chinese government shut down miners in the country virtually overnight, the mining output of around 200 exa-hash had collapsed to around 80 exa-hash. But the network adapted very quickly. There were no block generation outages or other problems. Only the price had fallen, but that has nothing to do with decentralization but with speculation. In the meantime, the exa-hash size has increased again, as the miners have moved out. For me this was a good proof how well decentralized and stable the whole system is, even if a big country bans mining activities.