BGP was intended for a specific niche. Earlier, there was the ARPANET, operated by BBN out of Boston, and peripheral stuff connected to it. Early Internet thinking was that there was a "core" with its own routing protocol, and BGP was how the core communicated with small peripheral networks. BGP wasn't intended as the core routing protocol.<p>Mutually mistrustful routing is hard. I wrote some stuff on this in the early 1980s. The best I came up with was a scheme where forgeries would be detected, and once the source of the forgeries had been kicked off the network, the system would heal itself. (Asymmetric cryptographic signing had been invented but wasn't yet used or trusted.)