I may have to pull rank here a bit, having worked with Steve Jobs.
What Steve was referring to was form factor and feature set. People do know what they want in an emotional/goal sense. In terms of major functionality, people do know what they want. In other words, people knew they wanted their lives to have a soundtrack. They just didn't know that would be solved with a memory device in their pocket.
If you have the ability to make an empathic leap over a lot of experimentation and discovery and evolving taste and visualize the ideal way your product solves the basic need, then you don't need a focus group for the MVP.
(this is a whole other discussion, but focus groups are difficult to derive actionable information from. Use a moderator who has done extensive work in prototyping to weed out comments of people trying to wear the 'product manager' hat and find the pure expression of personal interaction with the product.)
Any client exposure of product features needs to focus on the end goal, not be sidetracked by the means of interaction to use the product.
Steve Jobs was not an inventor and he was not a designer. He was the world's best curator.
Anyone creating and evolving a product should certainly get client input, but then be willing to accept or reject that input based on deep empathic understanding of the product's ultimate goal, which is almost always to effect a change on a more conceptual and even emotional level.