The travesty is that ISOC has given up a sure-fire stream of $55+ million/year in tax-free income, along with the ability to easily grow that to over $100m/year with price increases - all for just over $1.1 billion.
As any r/personalfinance reader can tell you a rule of thumb for endowments is to spend a maximum of 4% of your assets each year. This means $44m from the $1.1bn, which means ISOC is immediately worse off than they were forecasting for this year (~$55m). Alternatively use the Yale method, which in today's low-return market will yield similar or worse results.
Moreover it's clear that ISOC are not behaving as the sharpest of investors, so we can imagine that the endowment might be be poorly managed or over-spent.