Because of the Wife Factor. Getting people to convert requires getting past a lot of social inertia. It requires you to first convince them that the convenience of streaming services isn’t actually worth paying for. Then it requires an elegant onboarding experience. Lastly, Plex simply makes remote access easy. Sure, you could fiddle with reverse proxies for Jellyfin. But that’s easy to mess up. Instead, it’s much smoother to simply sign into Plex.
I can talk my tech-illiterate “My google chrome desktop icon got moved, and now I don’t know how to check my email” mother-in-law through Plex’s sign-up process over the phone. In fact, I did. It’s familiar enough that anyone who has signed up for a streaming service can figure it out. I can’t do that with Jellyfin, because their eyes glaze over as soon as you start talking about custom server URLs or IP addresses. Hell, my MIL’s TV doesn’t even have a native Jellyfin app available on the App Store. If I wanted to install it for her, I would need to sideload it.
Jellyfin does a lot of things right. But by design, the setup process will never be as elegant as Plex’s, because that elegant system requires a centralized server to actually handle it. And centralized servers are exactly what Jellyfin was built to rebel against.
To be clear, I run both concurrently; Jellyfin for myself, and Plex for friends/family. I got the lifetime Plex Pass license a decade ago, and it has more than paid for itself since then. But it sounds like a bunch of my friends and family may end up switching to Jellyfin if they don’t want to deal with the PlexPass subscription.