Really don’t feel comfortable defending OpenAI in any way because there is a lot to complain about but ads for paid services that cost a lot more than $8 per month is not really an anomaly. Look at Amazon prime, prime video, Hulu, airline flights, any major newspaper subscription, YT premium, etc, etc. I get the annoyance but just cancel the service if you don’t want ads or pay for a tier that isn’t subsidized.

Netflix has an ad-supported paid tier. https://www.netflix.com/ads-plan