This idea of being visionary is steeped in mythology. Steve Jobs is famous for not doing focus groups and being visionary. Yet he appears to read numerous emails from customers and is also famous for snooping around his retail stores. So clearly he takes into account customer feedback.
I have been researching lean startup and customer development and they are trying to resolve this paradox with the now overused concept of the pivot. The premise is you have to have vision and stick with it ("You can't split test your way to a vision"). You also have to gather customer feedback and metrics. Once your metrics stall and show diminishing returns on tests and changes, it's time to consider a broader change or pivot.