I remember something along the lines of "poor people are poor because they don't have what they need to survive, so simply sharing the resources they do have isn't enough"
This is almost definitely it: Mutual Aid A Factor of Liberalism
Basically an extrapolation of these two paragraphs which contain your quote in essence:
But the truth is, mutual-aid isn’t a challenge or threat to the social order which produced hunger and precarity. The state is largely indifferent or even welcoming to it. In a world where the working class is increasingly being told to fend for itself, can we continue to call this “solidarity” with any honesty? If not, then what actually do these practices do for us?
The problem of poverty is precisely that we don’t have the shit. Let’s get a few very agreeable things straight, which really clarify why mutual aid is wholly insufficient: 1. The world of private property and wage labor drive poverty and produced a number of social problems. 2. The poor and working class is characterized by lacking reserves and does not have free time, and 3. The poor and working class do not have the unpaid labor and unused property by which to alleviate these problems directly without going to the source keeping it from them.
Was it this? https://www.leftvoice.org/mutual-aid-networks-toward-a-constructive-critique/
*Probably not. You said the article was "fairly long." Bubbalu, above me, probably got it.
I don't know what the article is, but I'd love to hear from this person who participates in mutual aid who thinks doing so is enough