Ethernet as used in almost every facility has not practically been a shared-medium protocol for decades. The citation of "token ring" sort of dates your notion of "Ethernet."

The Ethernet spec is over 5,200 pages, including the old multi-drop buses, but the parts of the standard that specify the physical layer and actually get used, including 10/100/1GBASE-T and the fiber Ethernets, cannot support more than one endpoint on a wire.