400k would last me 13 years for a rack, power and 10Gbit/s bandwidth at my colo place (Switzerland, traditionally high prices)
Regardless, the ongoing interest on $400K alone would be enough to pay colo fees.
I don't know what kind of rates are available to non-profits, but with 400k in hand you can find nicer rates than 3.3 (as of today, at least).
that covers quite a few colo possibilities.
Another thing overlooked in this debate: Data center costs normally increase at the rate of inflation. This is not included in most estimates. That said, I still agree with the broad sentiment here: 400K USD is plenty of money to run a colo server for 10+ years from the risk-free interest rate.