I think your essay is well-focused and makes some good points. I particularly like your observation that "Without prior knowledge, imagination loses its focus and is not always fruitful." I do have some editing suggestions for you:
Even though my siblings were much more creative than I was, they could never design better websites or edit pictures better than I. I attribute my success to my relatively superior knowledge rather than to my imagination. And I think even for human survival, first comes the knowledge, then the imagination. Without prior knowledge, imagination loses its focus and is not always fruitful.
In my A Levels Psychology I studied that even though intelligence is inherited, without proper exposure and development a person might not be as intelligent as his parents. This exposure and development are not inherited but learned, and learning comes from experiences and knowledge. Therefore, without a proper IQ level, a person is less likely to be as imaginative as would be a person with a developed mind who has a higher IQ level.
Even in the past, discoveries in sciences were not made without prior knowledge. Newton, Einstein and Galileo all were capable and learned people. Einstein's greatest discovery of the nuclear bomb was not merely a piece of wandering imagination. In fact, such an intricate mechanism cannot be developed without prior knowledge and observations.
Imagination does play its role in human progress, but it cannot work alone without prior knowledge.
One thing I might point out is that Einstein did not "discover" the nuclear bomb. He provided a limited amount of theoretical research towards the project and did not work directly on the creation of the bomb.
I hope this helps! Best of luck!