They said it in the statement, they quoted to chapter of the company that they should focus on AI for the betterment of humanity.
I can't say if this will work, but I think the message is pretty clear. No more random product launches like the GPT store, but rather focus on the core: building the AI, testing it and launching when it's safe.
To be honest, I've also found them getting too diluted in offerings. Why not let other startups focus on those things? Let Openai focus on the core models and give tools to others to build/finetune things. They can be the infrastructure of the AI world, they don't need to create every product.
Again, we will only know in the future if this is the right decision. But there is a strong case to be made here, especially with the company's original mission and non-profit status.