> The only argument the screen camp had was "no serial port support in tmux".

No, the screen camp has the valid argument that licenses matter and tmux is not GPL software.

From the end user perspective, it makes zero sense to avoid software just because it has an open source license that is more liberal than GPL.

You seem to completely miss the point of the GPL.

You're welcome to explain it to me. What benefits do I get from switching from MIT software to GPL one as an end user?

In your view of the world what is an end user?

If we're talking about someone who has received a binary copy of software, then isn't this obvious?

The MIT license permits the distributor to close the source of what they've redistributed, in original or modified form. Potentially depriving the end user of the freedom to view/modify/distribute the source.

Permissive licenses prioritize rights of the software redistributors at the expense of the end users.

https://en.wikipedia.org/wiki/Copyleft#Freedom

The MIT license permits some other developer to fork the source and close it off, but as an end user of this particular software that is under MIT (meaning that source is available, and I can take it and modify it if I need to), how does that affect me?

tmux is MIT-licensed, right? The MIT license is very similar to the (3-clause) BSD license which makes it upward-compatible with the GPL (you can incorporate MIT- or BSD-licensed code with GPL-licensed code).

Edit: and to your point of a distributor withholding the source: yeah, so? If there ever came a point where the current maintainer closed its source (unlikely), somebody with a copy of it can step in with a fork. Or the project can die a deserved death for closing its source. At this point the benefits of open source are pretty much obvious to anyone with a brain, and closing the source of an open-source project is practically suicide.

I switched to tmux and I switched back due to the weird server/session/window/pane model that makes no sense and prevents me from showing different windows or layouts on different clients. 4 levels of objects is ridiculous and when you end up with less capabilities than screen, what are we doing?

I would love to switch to a modern, maintained terminal multiplexer, but it would need to, well, be good at multiplexing.

Server? I never encouter that while using tmux.

You can just use one session if you like, and if you do, it's the default, so you don't have to do anything special.

Tabs and Windows work similar as in screen as far as I can see.

No, you can't. Using one session, every client have to show exactly the same panels with the same layout in the same terminal size.

I found it incredibly slow, especially running Neovim. Zellij was missing super basic functionality, so I went back to screen.

A long time ago tmux was a little bit slower. But if you say that it's super slow for you now, then probably it's something to do with your config / setup.

I haven’t done serial port stuff in many years, so I ask this in ignorance and I give you permission to laugh at my naïveté. Can’t you just run tip or something in a tmux or zellij window and have basically the same thing?