Above a certain threshold, and if you can't raise admissions, a random selection process is perfectly fair.
It's certainly fairer, IMO, than having a perfectly objective ranking system that mirrors biases in society, and then using affirmative action to counteract those biases.
Fair isn’t necessarily the most important metric for schools. If your parent is a billionaire it’s perfectly rational for them to prefer you over somewhat more qualified applicants.
Donations are appreciated, but so are connections.
Mixing the extremes of intellect, social connections, and wealth offers benefits to each group. It’s an old formula and arguably a larger factor of what makes an elite school than its faculty.