For a business headed open source project, it's still about the community. In this case, the business tends to take a defining and often controlling role in the community. This has plusses and minuses. On the plus side, if a business has a vested financial interest in the project, there is financial incentive for continuity. On the minus, when the company's financial interest no longer aligns with the community, many of us retain scars from rug pulling and switcheroos.

So understanding the long term stability of a community is more than just checking whether there is a company backing the project. It is important to analyze the nature and diversity of interest. I think it's just as important that there exists a larger community that the business depends on for extra feature + bugfixing work which is capable of forking. When this is possible, it is much less likely to be necessary.