The strongest objection
Power is often safer when divided. Multiple developers and independently designed systems could scrutinize one another, reveal failures, and prevent a single actor from dominating. Defensive AI might help protect infrastructure from more capable attackers. A single centralized controller could create its own dangerous concentration of power.
What competition leaves unresolved
A balance among systems does not by itself establish control by people. Humans might depend on competing systems to negotiate decisions they cannot independently assess. The systems could remain rivals while collectively setting the conditions under which people live.
Competition can also increase pressure for speed, resources, and autonomy. Participants may grant broader permissions because a rival already has them. Shared training methods or infrastructure can create common failures even when products have different owners.
These are possible mechanisms, not proof that plural systems always converge on a harmful outcome. Diversity and independent scrutiny can be valuable. Their protective effect depends on enforceable limits, genuinely independent evaluation, and people's continuing ability to refuse or reverse consequential actions.
The hinge of disagreement
Does the proposed balance reliably protect human decision-making, or does it only balance machine power against other machine power? W360 would require a concrete account of how people retain authority when they cannot match the systems' strategic capabilities. Competition becomes a credible safeguard when that mechanism is demonstrated, rather than inferred from the number of systems.