Creativity comes about by connecting pieces of knowledge. The more experiences you (and your partners) have had in life, the more diverse those pieces of knowledge and the more likely you will be to come up with a truly original idea.
If experiences ignite creativity, experience kills it. The more expertise you possess in your chosen field, the more reasons you can find for saying no to a fresh ideas.
Experience leads to habit. You learn the easiest and fastest way to perform a task. You keep performing it that same way over and over, never experimenting with alternatives.
Also, expertise makes you unlikely to ask naïve questions – and many great innovations have resulted from such questions.