Because they're always asking the wrong question: "How?"

“How can we get there first?”

“How can I have more sex?”

“How can we beat Google?”

“How can I get his attention?”

“How can we get more press?”

“How can we increase our profits?”

“How can I lose 20 pounds?”

“How can we do this cheaper?”

“How can we get more users?”

“How” is the wrong question when trying to generate ideas.

Why?

It's the wrong question because “How?” asks for a single answer, the best answer.

Framing the question this way for your brain short-circuits divergent thinking, which is what we need more of.

Far more effective to ask, “In what ways could we _____?” or “What are some ways we could _____?”

It's a subtle change and WILL feel cheesy the first time you try it.

But this subtle change makes all the difference in the quantity of ideas you generate. And quantity of ideas leads to quality of ideas. So get brainstorming and make something interesting.