One of the Internet's key design objectives was to be robust to a single point of failure. So much about it's design and implementation is redundant. It is interesting to me to learn that inter AS routing is described as brittle. Inter AS routing is at the very core of what we call the Internet, the network of networks. It seems that there is no redundancy for inter AS protocols, and that this is potentially a single point of failure for the Internet. Would it be possible to have multiple competing inter AS protocols?
I suppose that the answer is probably yes, and that it may someday happen. It seems that the inefficiency associated redundancy and competition is necessary. I suppose that the same holds true for the Internet protocol as well. Maybe instead of slowly transitioning from IPv4 to IPv6, what is really happening is that we are transitioning from a single Internet protocol to multiple Internet protocols.