That bogus “If I had asked people what they wanted, they would have said faster horses” quote was never uttered by Henry Ford. It's used by people who hold the customers in contempt—who think they're such stable geniuses that they don't need to ask. You hear it a lot at start-ups with self-proclaimed "genius" founders.

Ford, however, did not hold his customers in contempt, and he did not think that those customers were such idiots that they'd ask for the impossible. When he did ask, they said "financing."

Ford did say "Any customer can have a car painted any color that he wants so long as it is black" (from his own book "My Life and Work"). That, however, was about the need for a single standardized model to improve assembly-line efficiencies. The customer had conflicting goals: color and price. Keeping the car black brought the price down considerably, which turned out to be more important than color choice. The decision was verified empirically. Ford at the time didn't lose a single sale due to the lack of color choice. Of course, the market (and tech) changed over time, and colors became feasible, so cars eventually came in colors.

So, the issue here is that customer-driven products focus on user needs (which are not all weighted equally) vs. practical concerns and costs. It's a balancing act. Ford's customers needed to have transportation, but they did not need color. Ford made the right choice. The best way to uncover those needs, however, is in conversations with actual customers. That's what "customer-driven" means: not that you idiotically build stuff that pops into the mind of a random customer (that way lies "The Homer"), but that you put the customer first in deciding what's important. It's _our_ job to both do the balancing and create the best solutions to the customer's problem (and needs), but we ignore our customers' input and direction at our peril.