I don't see how that is an argument that open source software is inevitable. If the only way to make money is to sell access to a physical resource as a servic

I don't see how that is an argument that open source software is inevitable. If the only way to make money is to sell access to a physical resource as a service and give the software away for free, then yes, I'll have to give my software away for free. But that doesn't mean I have to give the source to my software away for free. In fact the economic incentive may be to not give away source code, because giving away source code will make it easier for people providing competing resource access services to develop their software.