You can easily employ redundancy for core services. Core functionality doesn't need to be synonymous with central point of failure. For example, you have three healthy copies of the core service running at all times, combined with failover. All software systems have a core function that must work or else the system fails, but that doesn't mean all software systems are centralized in any useful sense of the word.
The problem i would see with centralization of routing is not reliability, but rather susceptibility to censorship; as the old saying goes "The Net interprets censorship as damage and routes around it" - while one could argue that root dns servers are central-ish, they are hosted all over the world, so a single actor can hardly impose worldwide censorship. It is a known fact that malicious actors can manipulate BGP (see Hacking Team), but it is still better than putting all of our collective eggs in Google's basket...
Distributed things though, mesh networks, IPFS - that's what's giving me hope.
