They just don’t know about it yet. This is the role of advertising and marketing—effectively letting them know what you are doing and doing this in as engaging a way as possible. Read more about this in a museum context here.
Ads that are merely visually appealing will not cut through the noise. Carefully craft your message with an understanding of your market and test the message on a sample audience, if possible, making tweaks accordingly (or overhaul what you have and go back to the drawing board). Use images that allow your potential customers to imagine themselves in your world—visiting your museums, employing your services, using your product. Anything less will not grab their attention in our saturated environment. It will be effectively invisible.
Spend your marketing dollars wisely by building your advertising campaign on strategy.