I don't believe you're asking this in good faith because the answer is so obvious. But just in case, it's because OpenAI is by a ridiculously large margin the most well known player in the space and unlike the leaders of other organisations his name is known and he has a personal brand which he puts a lot of effort into promoting.
Why is it obvious. Google is a much more powerful profitable entity that has equally good models. Facebook uses data from Libgen. Both are highly profitable companies who could pay for resources but don't.
Anthropic, the ethical fork of OpenAI doesn't do anything much different nowadays.
OpenAI may have had a head start, but the competition is not far behind.
The two are seen on the picture together! So more similar they could not be. That highlights the irony and hypocrite of capitalism, of better say of human society.