While there will definitely still be places that are less impacted - those two will probably be near the first to become heavily damaged in terms of credibility.

Wikipedia has multiple controls that facilitate quality and authenticity of content, but a lot of them break down in the face of synthetically polluted generated info.

The cost of engaging with the editorial process drops to functionally zero as sock-puppets are trivial to spin up that are near-human in quality. Run 50 of those for n-months and only then use them in a coordinated attack on an entrenched entry. Citations don't help because they rely on the knowledge-graph, and this pollution will spread along it.

Really what's left are bespoke sources that are verifiably associated with a real individual/entity who has some external trust that their information is authentic, which is tough when they're necessarily consuming information that's likely polluted by proxy.

This is an arms race, except the second player hasn’t shown up to the game yet.

The regulators must sponsor fact checking AIs. Bing Chat is a start. Alas, the regulator’s as usual have no idea what’s going on, except this time the rate of progress is so large even technologists can’t see further than a year out. Scary times.