Did the computer scientist at Xerox really develop the first LAN, but had no backing from the company to further develop these technologies, later showing this to both Steve Jobs and Bill Gates?
Xerox developed ethernet. Was there a local area network preceding ethernet?
There was certainly wide area networking before ethernet, e.g. ARPANET dating from 1969.
There was also local networking even earlier, e.g. the IBM 1401, sold as a small mainframe in its own right, also ended up being used as a peripheral controller for larger mainframes; this arrangement could be called a network. But one feels it was not quite the same thing. So what was novel about the Xerox LAN?
Ethernet was designed to be a purely local network among peer workstations. And I think the Xerox Alto was the first general-purpose workstation in the sense that term came to be used.
So if you use the term LAN in that particular sense, I think the answer is yes, ethernet was the first.
Xerox developed the Ethernet, which is a LAN, but most likely not the first LAN.