Assuming users accept those ads. Like, would they make it clear with a "sponsored section", or would they just try to worm it into the output? I could see a lot of potential ways that users reject the ad service, especially if it's seen to compromise the utility or correctness of the output.
Billions of people use Google, YouTube, Facebook, Tiktok, Instagram, etc and accept the ads. Getting similar ad rates would make OpenAI fabulously profitable. They have no need to start with ad formats that might be rejected by users. Even if that were the intended endgame, you'd want to boil the frog for years.