cisco was founded five years later, in 01984, at which point regular ram cost on the order of a dollar a kibibyte, so the content-addressable memory you need to accelerate a router was maybe ten or twenty dollars a kibibyte
would people complain about the ip headers having unnecessary junk in them? certainly, but there is plenty of that in the actually adopted protocol header design too, so clearly it wasn't a showstopper
https://datatracker.ietf.org/doc/html/rfc791
there was no such thing as a router in the sense of dedicated hardware; a router ('gateway') was just a host with two or more interfaces
the ram used by ipv4 addresses was the same kind of ram used by the rest of the ip header and indeed packet
i mean originally you did have the imps but they were just looking at the arpanet node number; they weren't gateways
the switch from variable-length addresses to 32-bit addresses happened between ien 80 in february 01979 https://www.rfc-editor.org/ien/ien80.pdf and ien 111 in august 01979 https://www.rfc-editor.org/ien/ien111.txt
cisco was founded five years later, in 01984, at which point regular ram cost on the order of a dollar a kibibyte, so the content-addressable memory you need to accelerate a router was maybe ten or twenty dollars a kibibyte
would people complain about the ip headers having unnecessary junk in them? certainly, but there is plenty of that in the actually adopted protocol header design too, so clearly it wasn't a showstopper