The issue in the article could have been solved by running a long-running command with no output in screen or tmux. If ssh disconnects, just reattach.

no, because this example was site->site data transfer across the disconnecting link

yes, because the issue was not the site data transfer, but the idle SSH session(s) running the nc commands. When the idle SSH session got dropped, it took nc down with it and that stopped the transfer.

no need for tmux, nohup would have done the job.