In this article I will provide you a bunch of advantages of FOSS (free and open-source software). Often, when an open-source project adds useful features, they get adopted by other similar projects.
Also, the community has a big impact on the development of software and often adopt projects that are dropped by their creators.
As you may know, Ubuntu and Debian use deb packages, while Red Hat, CentOS, Fedora and other derivative systems use rpm packages, which are not compatible on DEB-based systems and vice versa. Until now, if you wanted to install a piece of software that does not had pre-compiled packages for a certain distro, you had to compile it from sources, which is an operation for power users.
Recently, Canonical has created the snap packages, a package format that comes with all the required dependencies built-in, so they are not distro-dependent like the deb or rpm formats.
Due to the fact that these packages are distro-independent, they have been adopted by other Linux distributions as well. If the snap package format was not open-source, it could not have been adopted by other systems.
Another good example is Wayland, a display compositor developed by the Red Hat team that will be adopted by Canonical, starting with Ubuntu 18.04. The Ubuntu coders have ditched Mir and Unity, their own display compositor, to adopt Fedora’s Wayland and GNOME.
A lot of projects that are abandoned by their own developers get adopted by third party developers which work for free in many cases, donations being the only means of getting money.
Canonical has decided to drop the development of Unity, Mir and Ubuntu Touch, so the Meizu and Bq phones that shipped with Ubuntu Touch as default do not receive official system updates.
Fortunately, UBports, a group of independent devs and community members, have decided to adopt and maintain the project. The same developers released Anbox, a framework that permits installing Android apps on Linux systems.
If you ask me, open-source projects will always get traction due to the community involvement, but from the lack of money, they will not compete with proprietary and expensive specific software.