I don't think it was out of petulance. DAZ gave them permission to keep distributing the figure, as long as they encoded it to V3 (which is free).

I think they just decided they wanted to pursue a different strategy. They want to make Lilin "open source." Like Linux and Firefox. They want people to be free to make modifications and add-ons, without having to RTEncode them. That means they have to start over, since DAZ (understandably) doesn't want to allow V3's shape, joints, map, etc., to be open-source.