First accept the fact that your team - despite their vaunted achievements in many areas - is not competent in ideation. Ideation is more than just pulling a rabbit (you've probably pulled one or two already, despite your collective lack of skill). It's akin to pulling a rabbit egg out of a hat, fertilizing it in a petri dish, and shepherding its development into a furry, scampering critter). It's a process of vision.

Your options are 1) develop this skill; 2) find someone who has. Weigh the effort and palatability of personal transformation vs setting aside the signal-detection machinery that has thus far excluded competent ideators from your circle.