This was happening well before LLMs, though. If anything, I have hope that LLMs might break some people out of their echo chambers if they ask things like "do vaccines cause autism?"
Are LLMs "democratized" yet, though? If not, then it's just-as-likely that LLMs will be steered by their owners to reinforce an echo-chamber of their own.
For example, what if RFK Jr launched an "HHS LLM" - what then?