IDK about elsewhere but East of the Rockies, at least, yes, they're basically used interchangeably in many contexts and nobody cares that a "Silicon Valley" story may in fact be about a company based a few miles from actual Silicon Valley. Sorta like how nobody outside New York cares about the distinction between the boroughs except maybe Manhattan, so including or excluding that information, versus just calling it all "New York", makes no difference to them (/us). In fact I bet a lot of folks think "Manhattan" and "New York (City)" are perfect synonyms, and really, it doesn't much matter that they do.