Am I not smart enough or doing it wrong?

I work with a lot of people from both bootcamp backgrounds and CS backgrounds that find applying fundamentals to technical interviews quite challenging. It's definitely hard, was hard for me to. The big mindset shift for me happened after I started interview others. I ran hundreds of interviews at Facebook and it really changed how I see the process. I realize this isn't helpful advice, "get a job at Facebook and do hundreds of interviews" but yes there is hope.