Innovation is doing different things. Going into new territories. Using new techniques. It is a paradox for most of us. On the one hand you are well aware that you have to take new roads before you reach the end of the present dead end street. On the other hand it is risky. It takes a lot of time and resources. Research shows that only one out of seven innovation projects is successful. So saying yes to innovation is a risk.
The underlying assumption of brainstorming is that people are scared of saying something wrong. In a period where employees still were scared to speak up, brainstorming was experienced as revolutionary.
Since the fifties a lot of people have challenged the effectiveness of brainstorms.