Back when Token Ring and Ethernet were battling it out, I was amazed at the sloppiness of the Ethernet protocol with collision detection at its heart. It seemed so clunky, and some reports said Ethernet collisions with even a few nodes slowed it down to Token RIng's 4Mbps. I never quite understood why Token Ring lost out ... but I didn't envision the big networks that came down the pike where Token Ring would have been lost. Switches made a huge difference compared to hubs, too.
Have there been any attempts to replace Ethernet that have actually gone anywhere? I suppose if there had been, I wouldn't be asking. But the idea of looking for collisions on so many dinky packets seems even clunkier to me now. What kind of real thruput do 10Gbps networks actually achieve today?