If they were on a sustainable trajectory they wouldn't be selling their soul for advertising money and other ill-advised revenue projects that contradict their stated mission.
They could be on a sustainable trajectory and still sell their soul purely out of greed. I'm not suggesting that Mozilla is actually doing that, I just wanted to point out the possibility.
Okay, but now you're changing the subject. The claim was that they don't have an endowment or that they're not investing it. But they are.
The truth is the vast majority of organizations with an endowment are not able to rely on it in perpetuity, I think there's a small subset of organizations that basically amounts to a bunch of elite universities. So it's not the intended or functional or actual purpose of any endowment to be permanent firewall against any conceivable financial hazard for all eternity. Having at one point worked for a non-profit myself that had an endowment, generally, what you do is you calculate how long an organization's operations could be funded by that endowment, and is one of a portfolio of metrics for gauging the financial health of a non-profit. It's more properly understood as a firewall to create some breathing space in the face of financial uncertainty. Again, reaching back to my limited stint at a non-profit, they withdrew a little bit from their endowment during the 2008-2009 financial crisis, as well as during covid. It's rarely the case that an endowment can fund an organization in perpetuity.
And maybe I'm crazy but if someone falsely accuses Mozilla of not maintaining an endowment, it seems relevant to point out that they do actually have one.