It is indeed! I think at some point K&K (aka "Shtetl World") may actually get finished; it had some successful playtests and some people were excited about it, and I think it's really fun. But it's a big sprawling project and there was a lot a lot of work to be done, mostly to make the content manageable and accessible and not just totally overwhelming for players. When Dream Askew came along I realized it was a perfect fit to take the Klezmers & Kabbalists content and make it into an economical, concise, rules-light game with already proven mechanics and balance.
Technically speaking, the Dream Apart playbooks are from Act 2 of Klezmers & Kabbalists/Shtetl World -- so the Klezmer, the Sorcerer, the Soldier, the Scholar, the Midwife, and the Matchmaker -- which, in the original conception of Shtetl World, would have worked sort of like "prestige classes" that you earn as adults, after completing Act 1 playing the teenaged roles (the Dreamer, the Rascal, the Dutiful Child, etc)...