To act like they were just responsible for the "UI parts" is ridiculous.
Product-wise, however, it's looking like good enough AI is being commoditized at the pace of weeks and days. They will be forced to compete on user experience and distribution vs the likes of Meta. So far OpenAI only managed to deliver additions that sound good on the surface but prove not to be sticky when the dust settles.
They have also been very dishonest. I remember Sam Altman said he was surprised no one built something like chat GPT before them. Well... people tried but 3rd parties were always playing catch-up because the APIs were waitlisted, censored, and nerfed.
b) AI is only being commoditised at the low-end for models that can be trained by ordinary people. At the high-end there is only companies like Microsoft, Google etc that can compete. And Sam was brilliant enough to lock in Microsoft early.
c) What was stopping 3rd parties from building a ChatGPT was the out of reach training costs not access to APIs which didn't even exist at the time.