"it's unlikely that the commercial entity will vanish overnight"
That seems like bollocks, but more importantly commercial entities abandon software all the time. If you build your business on a software/framework that a company discontinues you are out of luck. With OSS, you are in practice out of luck too, but you have the options of trying to maintain the software yourself, or trying to co-fund a developer to take on the project.
I am not denying there is a problem with OSS funding. But saying that relying on proprietary software is more stable appears to be a statement built upon bias rather than evidence. It depends on the context. We have seen RT linux outlive commercial soft realtime OSes like PharLap. But, that does not mean you should build your business about a GitHub project with a commit a month for the last 2 years (you could always hire the dev to keep the project alive). Context is everything.
Biting the hand that feeds IT
