implying all (or most) distros are the same
No, they aren't. Some distros fill a niche (for example, Gentoo, Guix, Alpine, Source Mage Gnu/Linux) and others offer stability and/or a lot of well-maintained packages (Arch/Artix, Debian, Kubuntu). There is also the matter of trust and security; Not all distros have a good track record. Also, maintaining a large catalog of packages takes a lot of effort. That being said, there are a lot of distros that don't offer any meaningful advantages over other distros (which means they are likely worse than others since as I said, it takes a lot of effort to maintain a distro).