It’s not sunk cost, dude. We agreed that $120 will get them 5 years of service that meets their needs. Even if they switch to jellyfin after 5 years, they still got their money’s worth.

It’s only sunk cost if they are worse off than if they had switched earlier. I guess if you’re arguing that they would still have $120 if they switch today, I would argue they should still pay that $120 toward jellyfin’s development. And that’s assuming they have time to switch to jellyfin AND it fits 100% of their usecases, either of which could be untrue.

Or Plex currently does everything they need it to, and $120 for 5+ years of keeping that going without any interruption of service is very reasonable. In the meantime, jellyfin will only get better and there might even be other options available by then.

Stop trying to make the issue black and white, one-size-fits-all. There are perfectly legitimate reasons for people to use both Plex and Jellyfin.