Context window is a limitation, but have we actually hit the ceiling wrt scaling that? For GPT, you need O(N^2) VRAM to handle larger context sizes, but that is a "I need more hardware" problem ultimately; as I understand, the reason why they don't go higher is because of economic viability of it, not because it couldn't be done in principle. And there are many interesting hardware developments in the pipeline now that the engineers know exactly what kind of compute they can narrowly optimize for.
So, perhaps, there aren't swarms yet just because there are easier ways to scale for now?
One LLM is limited, one obvious limitation is its context window. Using a swarm of LLMs that each do a little task can alleviate that.
We do it too and it's called delegation.
Edit: BTW, "swarm" is meaningless with LLMs. It can be the same instance, but prompted differently each time.