Many such pieces of software exist both backed by non-profit foundations, and not. Before the Linux kernel was running the world, it was primarily maintained by volunteers. Also consider the myriad of Linux distributions that don’t have corp overlords. Or pick a *BSD. Or anything you watch video content with: ffmpeg, vlc, mpv. Or even various programming languages such as ECMA Script, Python, Ruby, C, C++, etc. Hell, even Lemmy fits into this category. There literally is a whole slew of software not directly backed by money and still maintained that literally runs the world.
I always read and appreciate these posts. Thanks