OpenAI have literally gone out of their way to explicitly support this sort of thing. As they did with OpenCode.

Honestly, this just looks like what Dylan of SemiAnalysis suggested on Dwarkesh – that they've massively under-provisioned capacity / under-spent on infrastructure.

That would honestly be a comforting answer if true, because I would gladly take 'we can't afford to do this right now' over 'we are self-preferencing, and the FTC should really take a look at us, even if we're technically not a monopoly right now, since we're the only strongly-instruction-following model in town and we clearly know it'.