When you experience a modicum of success in life, it’s easy to fall into the mindset that this means the system is fair, your success is entirely the result of your own intelligence and hard work, and those without success just must’ve not tried hard enough.
The long-documented phenomenon of people grossly underestimating how large the income ratio is between the median earner and the 1% also plays a large role. It makes it easier to think of oneself as economically closer to the 1% than the bottom 25% even though by raw numbers and ratios they’re way closer to the latter than the former.