I think it's because OpenAI's leadership lacks good taste and talent. Realistically, they haven't shifted the needle with anything really interesting in 2 years now. They're using the inertia well but that's about it. Their model is not the best, the UI is not the best, and their pace of improvement is not great either.

I find the chatgpt-4o advanced mode to absolutely be "really interesting". And the video input they showed in the demos (and hope would same day release) could be a real game changer. One thing I would like to try, once that's out, is to put a computer with it amongst a group of students listening to a short lecture about something outside its training set and then check how the AI does on a comprehension quiz following the lecture - my feeling is that it would do significantly better than the average human student on most subjects.

Anthropic currently does much less hype stuff comparing to openai. It's remarkable that openai was like this until the GPT-4 release, and completly changed since Sam Altman started touring countries.

One theory I heard is that Dario was always interested in RL whereas Ilya was interested in other stuff until more recently. So Anthropic could have had an earlier start on some of this latest RL stuff.