IP - and especially IPv4 - is a challenging protocol for decentralized networking. The protocol is really more suitable for a local network within a single routing and administration realm. That does not reflect today's internet.
Applications tend to assume that IP addresses are globally unique. ISPs depend a lot on each other to handle routing properly. Occasionally we see a route leak when someone screws up. Sometimes it even happens deliberately. And it's entirely possible that malicious routes are announced on a regular basis to conduct clandestine MITM attacks. Technical solutions for automatically determining which ASNs should be allowed to announce an IP prefix remain problematic. And BCP 38 - while it helps to deal with DoS attacks and certain security issues - also breaks some very useful approaches to deploying high performance/scale applications.
The internet is currently far more centralized than most people like to admit. The reality is that both DNS and IP are handled by delegation from a central authority. For instance, proof of IP address ownership remains outside the scope of the protocols. Network connectivity still remains based on trust relationships. That is fundamentally incompatible with a decentralized and ad-hoc approach to networked applications.
There are many network operators who have been shown untrustworthy. The design of the internet hasn't quite caught up yet.
Today's internet supports multicast, unicast, anycast, broadcast, and geocast addressing. IP is a connectionless protocol designed to facilitate communication from one network node to another. The protocol is designed to be routed through dynamic, unreliable networks. IP is really not that challenging and there's a lot of other layers that make its job easier.
And it really has nothing to do with centralization or decentralization. It's peer to peer. Your peers can be anywhere and you can send and receive anything, out of order, connectionless. This is fantastic for decentralized distributed networking.
Applications can 'assume' anything they want; that's the application, not the addressing protocol. Everyone who has read RFC1918 knows IP addresses are not unique.
And there is no way to ensure a route doesn't have a malicious actor. It's been shown time and again with networks like Tor that it doesn't matter what layers of security or obfuscation or decentralization you add. A bad actor on a route will be able to identify or mess with your traffic. Your application is the deciding factor in the security of the connection.
DNS and IP are not handled for everyone by a central authority. Both are independent protocols which can be used across the internet without a central authority's authorization. Of course IP addresses are more closely guarded, but like you mentioned before, advertising an invalid range of addresses works all the time. And DNS is not even needed to use the internet! Public domain registration using specific TLDs does have centralized control bodies, of course, but that's necessary to prevent conflict.
The internet is a web of trust. That will never, ever change. The reason it will never change is we all want something for free.
If you wanted, you could pay for and bury fiber-optic cable from your home to every place on planet earth that you want to make a network connection to. Then you wouldn't have to trust anyone, and when someone taps into your fiber or cuts the connection, you could (hopefully) determine that your connection is no longer "safe" or "reliable". But this is not very practical.
The internet fixes this by allowing any network to help any other network get around common network problems. We help each other because it is mutually beneficial. When that mutual assistance breaks down you get problems like the Comcast-Netflix debacle. No internet protocol or addressing scheme will route around a monopoly on the network. The only "decentralized" solution is a bunch of people on a wireless mesh network and a satellite link, which will still result in Netflix not being practically usable.
But please, keep believing that an addressing scheme will somehow keep you from having to trust a foreign network. Good luck getting House of Cards to stream.
Applications tend to assume that IP addresses are globally unique. ISPs depend a lot on each other to handle routing properly. Occasionally we see a route leak when someone screws up. Sometimes it even happens deliberately. And it's entirely possible that malicious routes are announced on a regular basis to conduct clandestine MITM attacks. Technical solutions for automatically determining which ASNs should be allowed to announce an IP prefix remain problematic. And BCP 38 - while it helps to deal with DoS attacks and certain security issues - also breaks some very useful approaches to deploying high performance/scale applications.
The internet is currently far more centralized than most people like to admit. The reality is that both DNS and IP are handled by delegation from a central authority. For instance, proof of IP address ownership remains outside the scope of the protocols. Network connectivity still remains based on trust relationships. That is fundamentally incompatible with a decentralized and ad-hoc approach to networked applications.
There are many network operators who have been shown untrustworthy. The design of the internet hasn't quite caught up yet.