I ran into so many roadblocks when I started seriously looking into going into academia when I was 16-17; if you don't have top science fairs or olympiads your chances of getting into top academic undergrads are already at risk, which has negative compounding effects down the line compared to the positive compounding effects of those that do get these, especially if you are a white or asian male. Close relatives of academics and people going to top magnet schools in major metro areas have huge headstarts compared to everyone else. Having a good IQ is just one of many requisites into going into academia, accomplishment-oriented credentials are much more valuable in your early career than things like regular standardized test scores
Many friends from grad school have tenure-track jobs. None of them, as far as I know, participated in these contests. I would bet that things effectively reset once you start grad school and again once you’re in a faculty job.
It is true that academic recognition tends to snowball. Winning your nth grant or fellowship is exponentially easier than the first one “because you have a track record.”
i dont think the math adds up.
As far as whites, alumni preference is typically as strong or stronger a weighting than affirmative action in undergrad admissions, and segregation wasn't outlawed until around 50 years ago meaning there are less alumni for non-whites to draw on, and many of the schools received federal money during segregation.
One of the most tried and true routes to getting into the best academia-oriented colleges (Harvard, MIT, Caltech, etc.) is to win one of the big science fairs. I am not sure what they are called or who their sponsors are these days, but they used be sponsored by Westinghouse, Intel, and Siemens. Anyway, if you look at bios of winners or semifinalists, they almost always have a close relative in academia. Which in these competitions is actually a massive competitive advantage since your relative can get you into labs, access to equipment, and push you towards fruitful projects they quietly are guiding from the background.
Same with a lot of the international olympiads, very often the kids come from intense tiger parent families that are already in academia or do everything they can to get their kids the best physics/math/whatever tutors (the main exceptions to this are usually kids in large metro areas going to top magnet schools).
And then of course once you're in these top academic institutes, your relatives can further help you network and get into the best labs, show you how to get the best fellowships and academic internships to set you up for top grad schools, etc. Plus now that you have a top olympiad/science fair your credentials will give you a big plus in competing against others without them