The GPT's making the most money will be made by larger companies who advertise use of it and maybe make it a funnel to their in-app integration, or GPTs which are made effective by information that is proprietary.
This makes me think of the Alexa skills ecosystem which is full of low quality skills. Many of which have poor data practices abstracted away behind the scenes. How long until "Chat with your favorite character from [Intellectual Property]?" which is simply made to promote a new film or collect data.
