I can say with certainty that failure to be systematic about idea generation has led to many failed projects that otherwise could have been great successes. These projects were, in hindsight, "almost hugely successful", had we had the correct idea to pivot to. Sometimes only a tweak or an additional feature was required.
Also, a separate comment to this thread:
Edward De Bono's "Six Thinking Hats" is an alternative way of approaching innovative idea generation.