Facebook hasn't contributed one iota? Facebook has contributed an immense amount to the developer community, small businesses and literally everyone else.
Free communication with almost any human on the planet: check. Advertise alongside industry incumbents with any ad budget: check. Oh yeah and React, React Native, GraphQL, pyTorch, and a whole lot more.
"Free communication" in... exchange for personal data. But thats a price that is invisible to fanboys. Exploiting those who either can't understand or who can't afford the tiny cost of communicating with data privacy.
As for small businesses, its walled garden simply cannibalized their earlier websites and made every small trader dependent upon opaque and arbitrary discovery algorithms that can wipe them out without warning.
The open source projects you mention have multiple alternatives, many from genuine community projects that will sustain irrespective of a corporate sponsor.
Free communication with almost any human on the planet: check. Advertise alongside industry incumbents with any ad budget: check. Oh yeah and React, React Native, GraphQL, pyTorch, and a whole lot more.