That is a good point, I didn't consider people who had built a business based on Gpt-4 access. It is likely these things were Sam Altman ideas in the first place and we will see less such productionalization work in the future from OpenAI.
But since Microsoft invested into it I doubt it will get shut down completely, Microsoft has by far the most to lose here so you got to trust that their lawyers signed a contract that will keep these things available at a fee.