OpenAI is not changing to a for-profit. It[1] always was a for-profit entity, owned by a non-profit.
The big change is that the non-profit no longer owns the entirety (or even a majority) of the for-profit entity; it is now a minority owner.
[1] OpenAI as we know it today. OpenAI was once just the non-profit entity, but back then was just an AI think tank. In 2019, it formed the for-profit corporation as a subsidiary to raise money and build the tech that we now know about (and make money from any products built on that tech).
The big change is that the non-profit no longer owns the entirety (or even a majority) of the for-profit entity; it is now a minority owner.
[1] OpenAI as we know it today. OpenAI was once just the non-profit entity, but back then was just an AI think tank. In 2019, it formed the for-profit corporation as a subsidiary to raise money and build the tech that we now know about (and make money from any products built on that tech).