> Unless you create some sort of a an auxiliary business and get an acquihire deal most things will fizzle out.

This is acceptable. Why shouldn't most things started by people not willing to put in the work to keep them going not fizzle out? The important thing is that anyone who actually cares to can jump in and pick up right where the open source software fizzled out and get it going again. Anyone can learn from the code and use it for anything they want, even things that have nothing to do with the goals of the original project.

It's not as if there aren't countless examples of corporate vendors dying off and leaving their customers on the hook with nothing, or just changing the product drastically after the sale. At least in the open source case you have the option to fork the project and continue using it as you always have.