Multiple security issues in GNU Screen

It's surprising that upstream was involved in this. Around 5 years ago, I came to the (sad) conclusion that GNU screen development had completely halted. Is that still not the case?

Does screen have the functionality to add a new window to an existing screen without attaching to the screen yet?

Open source does have a problem with inertia whenever one piece of software ends and another piece is created to replace it, but there's no immediate incentive to switch, because it is a switch, not an update.

Though conversely, when someone buys the trademark for an existing piece of software, and replaces it with something entirely different, like what happened with Audacity, that's also bad. So there's no good solution.

Isn't this what distros are for? So e.g. Debian could decide to replace screen with tmux, possibly with some sort of compatibility package that takes all the same command line arguments as screen but uses tmux under the hood. (I've used screen very little and have never used tmux so I'm not sure if that would make sense in this context).