Yes, if you bust ass all your life, have parents with professional middle-class values (regardless of actual income) and work in what is likely one of the easiest professions to develop wealth with in a period of time when a software engineer makes an abnormally high income in relationship to peers in other professions, sure, you'll do well.
But that's not really the issue.
The issue is that children of wealthy parents, for sure, study and make an effort to do well in school. But the required effort is just a _fraction_ of what a child of a wealthy parent needs to do.
A wealthy parent can pay for a tutor for a child who doesn't have much interest or curiosity in preparing of standardized tests, and the tutor will guide him/her to the extracurriculars that academics value. By contrast, a poor child with no tutors and no particular desire to do test prep, all other things being equal, just won't do.
What will happen to the child of your cleaner when she wants to attend the expensive vacation holidays of her peers, where undoubtedly a lot of socialization will go on where many will exit college with opportunities that she won't have, because she wasn't in the right place at the right time?
What about if she wants to pursue a career that isn't really profitable for many years? A wealthy teenager can take a gap year, switch careers, pay for a psychiatrist if they have some mental issue that for them will just be a simple obstacle, but for someone without the means can be career-ending.
No one is questioning _your_ ability to reach for success. Just understand that for wealthy people, a lot of your effort was just unnecessary, and they likely arrived at the same place you did with with less stress, better sleep, more parties, many more days off and a lot more opportunity to just take life easy.
Your wealth required you to pick the particular career path that enabled it, but other choices would have likely ended either in poverty or much less wealth. A wealthy child can pursue his or her dream opportunities with far fewer concerns on that front, knowing that they're covered.
My parents came from a much poorer background than me. They busted ass, taught me the same values, still work hard.
Frankly, I just don't work as hard, but I went to a great high school with _very_ wealthy peers who taught me the secrets of the upper classes, and I purposely chose this profession as a software engineer to my advantage, which has allowed me to take gap years, travel the world, and do a lot of things that a lot of my peers, who work much harder, longer hours, and more stressful positions in other industries will never get to do. That's not a declaration of my skills, but rather an assertion of the deep inequality and unfairness of the system.