At the risk of repeating myself, let me instead explain to the uninitiated how one may be successful at treatment-free beekeeping.
The solution is using local bees and breeding like a mad person, ferals, swarms, any bees that survived your last winter, (Andrew has at least two hives that did that, these are now your local stock) and you multiply them. You take those two hives and turn them into five or 20 or 50 if you have the ability and then you try again next year. And when you get bees that survive consistently, then you work on other traits. You know as well as I how many have tried what you tried, either with BeeWeaver's bees (outside of BeeWeaver's climate) or any other, dropped hundreds of dollars, and blew it. All the time, I hear the argument "learn the basics and then try treatment-free" but in treatment-free, what I've outlined above is the basics. That's how it has to be done because that's just about the only way it really truly works.
If you want to know how to take two hives and make 50, I suggest grafting into a queenright cell builder (http://parkerfarms.biz/queenrearing.html). The limiting factor is equipment and brood donors. My equipment limits me to 27 nucs at a time. Two hives will probably put a hard limit at about 10 nucs. But if there are other hives to donate brood, the sky is the limit. At this stage, you want unnatural increase, to get as many new bees into your area as possible and let them figure out how to survive. Many of them won't at first, but the more years of adaptation you have, the greater the strength of the result.
I say this year was great. I lost all the bees that aren't going to survive a tough winter. And since I'm moving to Colorado, that's an important trait to have. It happened to Andrew too. This mindset that all hives should survive every year is conventional thinking and treatment-free is never going to stand up to that metric. That's not how it works in nature and it doesn't work that way in treatment-free. There is and must be an ongoing winnowing process that does and must kill some hives every winter and every summer. And some years, both summers and winters, are particularly harsh, but as Andrew has shown, there are always some that survive somewhere. It may be very few that take years to repopulate the area (naturally) but you as the treatment-free beekeeper use these things to your advantage and use your methods of rapid increase (I call it "Expansion Model Beekeeping") to give the process a kick in the hind end.