.. feedback loop allows TCP [to run][ congestion avoidance: If acks return at a slower rate than the data was sent out, that indicates that there is little bandwidth available, and the source throttles...
which does seem to be a far cry from TCP. While common lore (and the modern buffer bloated internet) has it that high RTT means little available bandwidth (and it sure does play havoc with the bandwidth product - giving rise to that lore fairly) - the design calls for packet drop rather than delay to indicate a link being overloaded. And while the source slows down - it does not actually throttles; it just awaits the ack - it wont slow down the next packets. It is just that the window won't grow further. So makes one think of the observations in RFC-2488.
"It says he made us all to be just like him. So if we're dumb, then god is dumb, and maybe even a little ugly on the side." -- Frank Zappa