Is self sufficiency ever going to be a thing in Fallout? Like, yeah people scavenge but there sees to be attempts to create actual economies, like the NCR. That doesn’t full on rely on scavenging supplies but actuall make stuff.
Short answer: I would campaign for the answer to be yes, but I'm not sure how well it can come across in a video game. We're also not going to get anything remotely leftist out of the Fallout series as is.
Long answer: under what system are we looking to see self-sufficiency? The modern late-stage capitalist system? Or outside it, with ideas of decolonization, or even Marxism?
Logically, I think there must be some attempts at creating a self-sustaining nation. Suspension of disbelief comes into play, of course, but scavenging can't possibly be that sustainable two centuries later. Raiding, maybe, but not scavenging.
I think we see this best in smaller settlements, with their own ranches, farms, and access to water. They have more reliable food sources. If we really want to get into it, Megaton has the means to clean its own water. Which is important.
Caps is a solid example of an emerging economy. They were (still are?) a real currency in the Hub, backed up against water. Everywhere else, however, caps seem to be a fiat currency (not backed up against anything). They have usage all through the wasteland and exchange rates with other currencies (paper money from NCR, Legion denarii).
Every time I've thought about this sort of thing, I come into the idea of resource allocation. NCR probably does manufacture some items in state. As a nation-state, they have the power to allocate resources to particular ventures. They have factories with people to staff and manage them. We already know from the Powder Gangers they have no issues with prison labor.
The Legion certainly has manpower. They may even have more than NCR, given their massive territory. I have my doubts about proper allocation of resources. Do these resources exist? They must, since keeping people fed is an excellent way of making sure you as the leader stay alive. Armies need food, water, and housing.
But both of these nations are very close to collapsing under their own weight. In different ways. NCR has, by the start of New Vegas, strained water sources. The Legion's not doing much else outside of conquering and appropriating. They've got the land, but can they use it?
They may be self-sufficient in a sense, yet unsustainable. Which I think should be the next question to "is there any possibility for self-sufficiency?"
That would be another matter entirely.