No evidence, I'm obviously lying ...
Btw, nepo is broader than "my dad donated". Most (all?) worthy positions in academia depend more on who you're friends with than on talent just by itself.
But that really has nothing to do with the original gripe about "day zero", which would generally mean getting into a masters or phd program, or perhaps an undergrad research project, where grades and standardized test scores get someone in the door -- social skills sufficient to hold a brief conversation about a science topic would be a nice bonus, but not really necessary.
And I confirm my previous statement, the immense majority of people who go on to take senior positions, particularly at big institutions, are made from day zero.
People who manage to make a career in science usually follow a specific educational path that includes a phd and postdoctoral research. No one would claim it is completely fair because there are many things that can block or hide that path (family situation; life events; lack of encouragement from teachers; being born in the wrong country; etc.). However, the system does not otherwise care about your background in any meaningful way.
You should consider the dark implications that you may be pushing misinformation that could discourage people who are gifted or intellectually curious and motivated from trying to improve the world by doing science.
Is there evidence?
It seems obvious that parents can increase or decrease the odds of someone starting a career in an "elite" field requiring advanced education like "Science", but I interpret your comment as suggesting that most scientists got their job by means of daddy donating to a university or some other silly fantasy.