"What do you do?" Let me paint the story.
In the current culture, each step of product development occurs in a separate silo. In the beginning, the stakeholder thinks their product is awesome! And in their head, it's probably the best product imaginable. By the end of the product cycle, they get a product that isn't what they imagined. Endless tweaks are made. Meanwhile, the product features are used to market and sell it.
Thanks to C S for making me think more about this and draw these images.