That's the problem, isn't it? Suppose that e.g. Wikipedia traffic is down year over year because of AI summaries and then they get fewer donations. Now something needs to be cut. It's a non-profit so "investor profit" can't be that thing.
If you then also make it so that it can't be workers, what's left? It's mostly either spending down savings (which isn't long-term sustainable) or sacrificing things that ought not to be, like infrastructure or servicing technical debt. So now you've put off a given percentage of layoffs for a few years until that catches up to you and sinks the whole foundation.