You can imagine and tell any story (build any product) you want. The art is rather to build a great story and often leaving things out even if they sound like a good idea makes the story way better.
Here are great insights about how Pixar creates great stories: http://www.prdaily.com/Main/Articles/Pixars_22_rules_of_stor...
Obviously not directly applicable to Product Management but I'm pretty certain that being a great story teller is one of the key skills for Product Management.