Most endowments are built through giving campaign drives of mostly small annual donations and bequests. The larger public endowments are from a lot of alumni giving over a long period of time. Yes there are some large angel donors, but this is not the norm.
If you are an alum and haven't dontated, then you should consider doing so. Uconn may not have 600,000 living alumni, but 200,000 isn't a stretch. $500/yr on average is $100M.
Presumably, you count Uconn as a reason for your success. Consider giving back, regardless of the amount.