Forced – does that mean they raided your servers and deleted the old source code or just that you want someone else to do new development following your whims but aren't willing to do it yourself?

One of the reasons free software is free is so that you can be insulated from the actions of the developer. There used to be a thousand word processors that were all mutually incompatible, and when the company died you were SOL. Lennart could have gotten hit by a bus, and Avahi would have needed someone else to maintain it. If you want to use Avahi outside of systemd now, you'll need someone else to maintain it. Sometimes these things happen and you have to take them in stride.