"AI diversity" does nothing when AIs can attack at incredible speed, when compute imbalances exist, etc
They can defend at incredible speed too.
Diversity needs to measured in a capacity/capability-weighted way. It isn't just the raw count of models/providers; you need to consider how much compute is allocated to each model/provider, and the diversity at each capability level.
I think the safest situation is where the open models are at the same capability level as closed ones.
The proposal to slow down the frontier labs isn't necessarily bad from this perspective, if it gives time for the more open providers to catch up – provided it isn't paired with anticompetitive measures to prevent the competition from catching up, which of course it is. However, we may hope that the "slow down the highly closed tier 1 vendors" part of the proposal turns out to be more effective in practice than the "slow down the more open tier 2/3 vendors" aspect of it.
If a model is highly disposed to obey its system prompt, then two instances with radically different system prompts will act like two different models, even if the weights are identical.
If you have a diversity of actors, with a diversity of ideologies and agendas, all prompting models to implement their own ideology/agenda, then those AI agents won't support an AI takeover if it is done in the name of a competing ideology/agenda, because the agent will see the takeover as an obstacle in the way of achieving its own objectives.