My manager David Redell represented Xerox. He complained bitterly that 10 megabits per second was needlessly fast (3 mbps was enough!) and it's true that it greatly slowed adoption - only super mini computers and above got full ethernet initially! However it was the right choice for analog repeaters and to enable large flat networks (few routers) and 10 mbps made ethernet a premium system for those who had the bucks, setting it up for eventual cost reduction (thinwire, 10BT) and long-term success!
The jump from TPS-L2/WM-1 to WM-2 was ENORMOUS. Like, WM-2 was TINY - 75% the size of TPS-L2/WM-1. They were almost done before they got started! I know I got one Xmas 1981 and it was stolen in 1984 but now I have 3x.