$1.5B pays for quite a bit of research. Or, more accurately, a lot of real estate speculation for the board of trustees to play.
Given that even most top research universities get by on a fraction of Harvard's endowment—while running largely comparable research programs—it's definitely possible to do without. Harvard obviously does strong research, but not that much stronger than the rest of the top 100 (top 200? 500?) universities. Certainly not 10–50× stronger!
My impression is that what really makes Harvard and other highly endowed universities stand out is their really aggressive financial aid. That's probably one of the things that's almost entirely funded out of the endowment as opposed to external sources or tuition and fees.
> Most universities get by with a dozen clustered on campus serving administrative, educational and research objectives
... A dozen what?
Looks like GP meant "a dozen data-centers", to compare the costs.