Ollama and Open WebUI, as far as I know, are just open source software projects created to run pre-trained models, and have the same business model as many other open source projects on Github.
The models themselves come from Google, Meta and others. Have a look at all the models available on Hugging Face. The models themselves are just binary files. They’ve been trained and there are no ongoing costs to use them apart from energy your computer uses to run them.
So what exactly is linktree?