Sure but that applies to literally a million other things. There is an absolute ton of shit that companies do that individuals can't which is still built off of others.
A company can go spend 1B on a new state of the art nuclear reactor which will bring in billions over it's life time. Will the physicist who discovered the underlying math see any of the profit? No, probably not. And if they do it won't be nearly a "fair share". Nor will all the publishers and authors who generated the learning materials that the people working for said company used to build it.
There is tons of public knowledge that can only be utilized with a huge investment, that's just how a lot of innovation works.
And OpenAI also has a ton of competitors. Sure they have the lead for now but thousands of other companies are also scraping and building LLMs.