Unless you are Red Hat, the answer is: about as much as eating lunch has to do with business models.
Whatever business you are in, you need your lunch, or you’re going to die. Likewise, but perhaps not quite so urgently, you need software. Open source is about getting the software you want for the minimum investment. It is cheaper and more efficient for those who need particular functionality to group together and provide it for themselves than it is to pay five different companies to not quite provide it in five different ways.
That’s all there is. End of.
So, when you read something like this: “Report: Pure Open Source No Longer a Viable Business Model”, what you are supposed to do is hit the keyboard violently and scream, “It never was, you morons! Get with the program!”
Selling support for software is a business model. Whether it is open source or not. That’s the business Red Hat is in. Not the “open source business”. There isn’t one.