The consolidation of mining power or "hashing" power into a smaller number of powerful computers is a risk to the decentralized model. I think that in the future two things will (need to) happen in order to allow a healthy and scalable bitcoin blockchain: 1) The mining algorithm will need to be simplified to allow all people and all devices (i.e. iPhones, iOT, Laptop, printers etc...) to participate in the mining network...2) Another layer of randomization will need to be created to allow the winning miner/node to be selected from the extremely large number of mining nodes that will exist based on 1) above. This is to improve transaction throughput and allow the solution to be scalable. Once the two items above are addressed then the only way for the government to stop Bitcoin would be to turn off the internet...