Yes this is true, although what happens when the profit motivated corporation doesn't make profits or loses revenue?

Isn't it more likely that a profit motivated OSS project will lose resources in this case, potentially affecting the product?

Check out RethinkDB, a competing product which had exactly this happen earlier this year. I don't follow the project closely, but the Linux Foundation picked up stewardship and development appears to be continuing, if at a reduced pace.

MongoDB is pretty popular, so while it would certainly be disruptive in the short term for the sponsoring company to go out of business, continued community development is all but assured.

That's a really good question.

I think the reality is that many large OSS projects are corporate sponsored, either directly or via companies paying developers to work in the project.

In a case like MongoDB, if the company faced difficultly or even went out of business, the product would undoubtedly be affected.

But since it's a popular open source product that many companies depend on, it seems unlikely it would die. For some of the successful companies using MongoDB at scale, paying developers to work on the project could very well be cheaper than migrating to something else.

I think this is true for large open source projects generally. It's nice to at least have the option of taking the code into your own hands if the company or people developing it decide to stop for any reason.