The problem with focus groups is 1) people say they want different things than they actually do, and 2) it's rarely representative, you'd need thousands of people. Then, once scaled, you lose details because it has to be more survey-like. Add in the leadership team's "vision" and you have a recipe for only making products for e.g. white men and ignoring the black woman haircare market.

It all has a place - but actual real data is probably the best way to figure out product market fit in my experience.