Because of the unusual history of OpenAI, the Government had far more of a say than normal for a company. Remember, OpenAI was originally created as a California non-profit (a charity doing work to create a better AI future). As a charity, it doesn't have to pay the same taxes as it would as a for-profit company, but in exchange it has more rules it needs to follow. And then it released ChatGPT, it exploded in value, it needed to raise truly absurd amounts of capital in order to get to the next model, and thus the lawyers had to spend a good long time extracting the company from the charity.
For very good reasons, the laws make it hard to go from a charity to a for-profit company- because if you could easily transition between the two you could game tax laws with ease. In the end, being allowed to do this required negotiations, and promising to keep OpenAI in California- where they would be subject to other California regulations and taxes in the future.
If they had a "normal" corporate history- had been founded as a Delaware S Corp from the beginning- then this wouldn't be a thing and they would be free to move as they like(1). But, being a weird charity probably helped them attract talent in the critical beginning phases (before it became a money race with Zuck), and it has consequences now.
1: Just as an example, Palantir moved their corporate headquarters to Denver from Palo Alto years ago without a peep from the CA government.