That's a great quote. It's important to understand that _listening_ to your customers isn't the same as having them design the product (which would be a mistake). In this case, the message that you should get from the customer is that "my horse is too slow".
That's probably a valid consideration, but whether you should take it into serious account depends upon your aims: Are you trying to shift the paradigm, and introduce something entirely new? Or are you simply trying to produce the best refinement of an existing process or technology.
Not every change is revolutionary, nor does it need to be. Constantly reinvent things, and you'll wear your market out. But customer-sensitive refinements are frequently welcomed by consumers (depending on what they cost), or at least accepted without complaint.
You can't simply blow your audience off, no matter how visionary Henry Ford might have been. Development of anything...a process, a product, an image, a brand, whatever...is a never-ending set of nested feedback loops from the target audience, or else it's eventually a failure.