https://github.com/jellyfin/jellyfin-meta/blob/master/polici...

> Jellyfin funds itself exclusively from donations by individual users. It does not and will not accept any sponsorship or other monetary compensation in exchange for features, priority access, support, or any other work by the community.

They spend the donations on paying for hosting servers, etc. They don't pay anyone a salary.

Their post highlights that your favourite third party client can be different. If your third party client is made by someone who'll accept donations, you should donate to them to keep your client going.

Part of the team needed it, part of it saw that as something that shouldn't go that way, so they did what you're supposed to do in open source and forked. Ergo they are very much against doing that for that specific project.