Balkanisation could be welcomed in some quarters
While people who think that all nodes on the Internet should be reachable think that managing the address space to avoid clashes/duplications is a good idea, some interested parties are not uninterested in the opposite. If, say the USA, China, and certain Gulf states were to decide, for example, that they would be the authorities to issue IP addresses for systems within their jurisdiction and decide to use duplicates of existing address ranges, then traffic would, of necessity, be NATed at the jurisdiction border by equipment they control. I would not be surprised if the Great Firewall of China already has this capability.
This would mean the local population would not see services provided outside their jurisdiction unless allowed to by the local authorities, and anyone wanting to provide services has to do so with the agreement of the local jurisdiction. It would be Balkanisation, but many people would actively want that.
Default global reachability and addressability has been fun while it lasted. It might not continue.