Really rich people

His unlikely rise from obscurity began when he launched a trade publication for data-communications firms in the 1970s. 

I often find that the answer to “how did they get so rich?” is frequently “doing something really boring.”

(That example Sheldon Adelson, but Robert Kraft (packaging) and the Koch Bros (processing) come to mind as well.)

A local angle:

A Boston Globe reporter who interviewed him in 1988 noted that his Needham, Mass., office was ratty, with a peeling vinyl cover on his chair. “I don’t need the trappings of success to feel successful,” Mr. Adelson said.