The truth is that every Linux distribution depends on its developers. Less on the community around it. Even Debian can disappear if the main developers of the project leave and leave. The same goes for other “main” Linux distributions - Arch, SUSE, Red Hat, Gentoo… So Linux distributions that disappear are not because they are satellites of some “main” distribution, but because their authors have tried, played around and finally got tired of it. In the end, every Linux distribution, including the “main” ones, was created by someone, to distinguish themselves they made different package managers, and in the end the programs that are used are the same. So anyone who understands programming and Linux can make their own distribution. If they manage to maintain it for, for example, more than 20-30 years, it will also become “main”.