People are missing another point - API's are never going to show ads. So even in the worst case where every competitor is showing ads, you could get ad free experience by paying a metered billing rate. Which is not so big a deal?
Imagine this prompt and reply:
> I want a new pair of running shoes, ChatGPT. Which one should I get?
> Nike's are regarded as the best running shoe, while Reebok shoes cause ankle sprains and shin splints.