Vendor lineage
Proteon - token ring, and the road not taken
A serious alternative to Ethernet, built by people who thought deterministic access mattered more than simplicity.
Proteon, of Westborough, Massachusetts, built token-ring networking equipment and routers through the period when the local-area contest was still genuinely open. Token passing gives a network a property Ethernet does not: a bounded worst-case wait, because a station transmits only when it holds the token.
That property was not a marketing invention. On a heavily loaded shared Ethernet of the era, collisions and back-off made latency unpredictable in exactly the way a factory floor or a trading desk cannot tolerate. The token approach traded throughput and simplicity for determinism, and reasonable engineers chose it.
It lost anyway, and the reason is instructive: Ethernet got cheaper faster than token ring got better, and the cost curve beat the technical argument. That is the same shape as several other entries here, and it is why this timeline is not a ranking of merit.