Not-for-profit means that 100% of the revenue is reinvested in the business (“mission”), rather than have a portion returned to owners/shareholders as profit.
Successful not-for-profit companies can have a problem of having more money than they can effectively deploy. This can lead to all sorts of problems: Overpaid staff; Inefficient operations; etc.
In the context of organizations, not-for-profit doesn’t mean they are designed to be not profitable; rather, it means their primary goal is focused on other goals than making the most amount of profit possible.
It’s also a misnomer that not-for-profits can’t make profits, it’s just that those profits are not distributed to the capital (owners, investors) of the organization.
https://nccs.urban.org/publication/registered-501c3-private-...
The opposite, not for profit, usually means, for loss, which is not sustainable.
An organization designed to be zero net will also die during hiccups and downtimes.
So if you want something to be sustainable, provide stable jobs, provide continues benefits to whatever it serves, "for profit" means it runs on less than it makes, allowing it to survive.
Basically, all the "not for profit" things die, and you don't see them around very long.