> if you're going to use an open source tool in your business's codebase, you'll inevitably need support, upgrades, and bug-fixes
I started using open source software and tools almost exactly 20 years ago in my career as an embedded software engineer. In exactly one case a company I worked for needed support from the developer, and in that case they hired the developer, ESR, to enhance his project, GPSd.
Perhaps it is different in other parts of the software world. From what I hear, the web dev folks like to shake and bake large collections of 3rd party libraries and tools. In my experience however, companies I've worked for have never placed the burden on open source devs to fix issues or add capabilities. They paid employees and contractors to do it, and generally, where appropriate, fed those contributions back to the community.
I do feel companies are not supportive enough of open source software, but I do not feel there is any burden placed on developers of said software other than those that they choose to take on themselves.