Re: well yes, but...
Plus, of course, Microsoft are not obliged to provide the non-profit discounts at all. They just figure that doing so will boost sales of the commercial versions as people get used to using them.
I've recently set up a non-profit using it and the cost vs on-prem means the break-even point would be >5 years, at which point the on-prem server would probably need replacing anyway. In this instance, cloud is both cheaper and more flexible for them; in other cases it doesn't work that way and depending on requirements the cloud solution may or may not be better.