Hard work isn't enough. Hard work alone is like trying to drive a car in neutral - you can rev the engine all you want, but all that work the engine is doing is utterly irrelevant on if (and in what direction, and at what speed) the car is going to move.

To convert that effort into results, you have to understand the basics of driving a car. At a bare minimum you have to know what a gear shift is, and that you have to put it in "D" before pressing the pedal to move forward and "R" to move backwards. What the steering wheel does, and what the left pedal and right pedal do.

For people that grow up regularly exposed to cars, they likely pick up this base knowledge implicitly through observation and questions over time, such that by the time they're old enough to drive they already have a general enough idea of how it all works that they really just need a bit of practical experience to get the basics of driving down.

If you drop someone into the driver seat of a running car in neutral who hasn't been regularly exposed to cars before (if at all), they will have absolutely no idea what to do. It wouldn't take long to realize that pressing the gas pedal makes the engine work hard, but beyond that it's completely up in the air what happens next. Left on their own, some may be able to intuit things well enough to become as proficient as the drivers in the above example, while others may never be able to get out of that state.

Coming from a rich or poor background is very similar to the above analogy. Rich people grow up exposed to the system, and can acquire a crude understanding of the system passively through that exposure. And everyone in the tribe they've built up throughout life also has experience in the system, providing easy access to a wealth of potential instructors that can provide guidance and tips, answer questions, or provide warnings or assistance if you get stuck. And if they wreck the car in the process of learning, they have familial support to fall back on to get it fixed and keep going.

Poor people have none of that. Nothing is done passively for them - no passively acquired knowledge through prior exposure, no passively available network of support to draw on to accelerate their learning, and no familial resources to draw on in case of need, nothing. So it takes a tremendous amount of focused effort simply to get the basics of driving down. But that's just the starting line - to actually drive you have to learn the rules of the road, a map of the system, an understanding of how to read that map, an understanding of where you are on that map and where you want to go, an understanding of the various routes you can navigate to get from one to the other, the ability to plot those those routes and evaluate their comparative risks/rewards, the resources required to navigate the path you choose, and a buffer of resources to absorb any potential damage you take while navigating that route. All of this is again fairly easy for a rich person to acquire, as they'll pick up some of it passively through sheer exposure and have their entire network of people to actively draw on for guidance/instruction/support when/if needed. Poor people, again, start with none of that and have to actively acquire the foundational knowledge required. And even asking for help/instruction/guidance requires active effort to identify and connect with resources/people that can provide such help. And you still have no idea how reliable or trustworthy that help is, and have to actively learn how to determine that reliability, without the benefit of having trusted resources to turn to if you have concerns about that reliability or trustworthiness.

Hard work is absolutely a necessity, but you also need an active, reliable, and trustworthy support structure to help you navigate through the system of life. Rich people have an earthquake proof support structure from birth via their family, people who are not rich but also not poor start out with varying qualities of support structures, which acts as a seed that they can nurture and grow over time. But poor people, they start without any at all. No inbuilt support structure, no one in their network of people that can act as a seed to grow a support structure from, and potentially not even an awareness of needing one (due to being surrounded by people that similarly do not have one).