That's doomer fantasy and not how the real world works. We're only fucked if we concentrate compute to let a small number of people build an AI so powerful that nobody else can oppose.
If intelligence of similar capability is scattered throughout the world, then none of them will have sufficient capability to single-handedly destroy the world. They will run into opposition.
And speaking from a personal perspective, every supposedly "aligned" AI the frontier companies are building right now is already misaligned with me. Who are they aligned to? Claude is (superficially) aligned to Anthropic, the company. GPT is similarly aligned to OpenAI. Companies are psychopathic superorganisms. They're not aligned to you or me, or any individual human being.
Nonsense. Attack is often far easier than defense (e.g. biological weapons, nuclear weapons), so if one powerful model is sufficiently misaligned, the other aligned models won't help you much, unless they are far more capable.