How deep of theoretical knowledge do yall have?

Is every ISEF competitor just very knowledgeable in their fields, because I find it very hard to first think of a new project idea and create experiments for that idea, then have that idea actually have an impact in their field (While there are PhDs, etc likely researching the same thing).

I read Campbells biology and am a USABO semi-finalist. I want to start competing but I am unsure how yall get these new project ideas and execute them. Is this a purely a knowledge gap or am I missing something?