The main question is who will regulate decentralization at the world level: the system itself or the government?
Am I missing something? Why would decentralization need regulation? When you talk about regulation, it makes me thing of some governing body. Like there should be a government above decentralization. Wouldn't that be sort of an oxymoron? You said the Internet was initially decentralized. Do you think that's changed? I'm under the impression that the Internet is extremely decentralized. I've heard that it's near impossible to shut down the Internet because it is decentralized. To answer your question in short, decentralization shouldn't need regulation.
The internet nowadays mostly relies on servers, there are many and geographically distributed. But it does not really work decentralized since data are stored on one server for example. IPFS is a project trying to decentralize the internet and create a real p2p hypermedia protocol.
Otherwise i agree with your oxymoron reference. Still you need to define rules in what frame the system governs in a first place. However, decentralization at the world level in terms of governmental processes, this will probably be one of the last implementations of blockchain. States are sovereign and will in a first place introduce blockchain on national level (concerning governmental processes). Otherwise, blockchain will be applied internationally in other areas where loads of data exchange and transactions happen, such as supply chain management, financial functions, digital identities and the energy market.