It's interesting that when we hear how much Bill Gates or the founders of AirBnb worked, we immediately conclude that working hard on a venture will make it successful.
In fact, the fact that successful founders have always worked hard only means that it is necessary to work hard; it doesn't mean that it is sufficient. We usually don't hear about others who worked equally hard, but didn't make it. So it doesn't mean that if you work hard, you'll be successful. It only means that if you don't work hard, you won't be.