I have a similar but slightly different take on the reasons for a rapid decline in participation. There is no doubt the size and incredible growth rate of the endowment is a major factor. There is no logical way for Princeton to say it needs anyone’s donation. The average gain on the endowment has been 10% per year for 20 years so expected annual earnings of $3.6 billion are more than the entire annual budget of about $2.9 billion. By any standard I am wealthy but if I gave my entire net worth to the University it would have absolutely no impact on the school or anyone’s outcomes.
I wouldn’t use the word “politics” to describe the disillusionment of alumni but rather the fact that Princeton has strayed far from its mission of truth-seeking and its once strongly held beliefs in free speech, civil discourse, and the exchange of ideas, even unpopular ones. Many students and faculty members self-censor and there is an overwhelming leftward tilt at the school that interferes with the pursuit of knowledge (wherever that pursuit might lead). Why should alumni support a school that no longer lives the mission we experienced as undergrads?
Finally, only a fool would contribute to an organization as inefficient as Princeton. While the University doesn’t publish per student expenditure data, adjusting for sponsored research and the PPPL, total expenditures suggest the University spends more than $250,000 per enrolled student annually. Where does all the money go? It’s an absurd waste of resources.
I’m grateful for all I received at Princeton but I don’t feel the need to continue to support financially a school that no longer believes in the values I do and that wastes so much money (which it doesn’t need) when I can make multiple contributions to other organizations that will have 100 times the positive impact any dollar I send to Princeton will.