Dave Snowden has a theory that innovation is triggered by starvation of resources, time pressure for a result, and a shift in perspective. See http://www.cognitive-edge.com/blogs/dave/2006/10/culture_and... where he makes the point

   Creativity is just one way, and not necessarily the most    
   effective to achieve perspective shift.  In fact I am increasingly 
   of the opinion that creativity is not a cause of innovation, 
   but a property of innovation processes, its something that 
   you can use as evidence of innovation, but not to create it. 

He has some interesting short videos up on http://www.youtube.com/user/CognitiveEdge that address innovation issues.

This might be true, but coming up with solutions to customer needs is a very small part of making software. Most of the day is filled with programming, i.e. translating your vision into actual software.

Creativity is often the result of great adversity. But in a roundabout way, you're right (but probably not in the way you think). See, by having fun, you're wasting time you should be spending solving the problem. Then just before the deadline, you miraculously solve the problem. Your fun beget your laziness,which beget your desperation,which beget your creativity.