How much is the typical dutch university paying MS/Google? Maybe 10k students x 200EUR/year = 2 million EUR/year.
Twenty universities come together to move to make Collabora+NextCloud work for them. That's 40 million EUR/year. How much do they need to actually spend on developers + infrastructure to make it happen?
If you look at the numbers that way, open source usually looks like a slam dunk.
The problem is coordination issues: actually getting people and orgs to look at it that way and spend the money that way, rather than just waiting for someone else to fix the problem.
They probably paying a tenth of that as big edu users. What you quote are the commercial starting price for a basic-ish license.