"solid center of a wheel," 1640s, perhaps from hubbe, originally "lump," the source of hob of a fireplace and hobnail, as in boots. A wheelwright's word, not generally known or used until c.1828; it reached wider currency in connection with bicycles. Meaning "center of interest or activity or importance" first recorded 1858 in writings of Oliver W. Holmes, and originally especially of Boston.
"Boston State-House is the hub of the solar system." [O.W. Holmes, "Autocrat of the Breakfast Table"]
"[E]verybody knows that Boston used to be called the Hub, meaning the hub of the universe. It may still be the hub, because the center of a wheel moves slowly." [J.P. Marquand, "Life," March 24, 1941]