As to the question on commericial queen replacement - we replace our queens no later in the 2nd year although a great deal of that comes directly from 2 queen units which get a new queen in the top unit (on top of what might be a 2nd year queen or a 1st year queen) and after 23days are combined. My observations and study tell me the young queen usually survives. I do care about hive longevitiy and I think most commercial guys would, even though they could use nucs and purchased queens to replace losses every year. Being commericial does not reduce our need for better stock.
As to survivor stock, we have run a yard of untreated bees for many years in working towards better stock. I would consider those my survivor stock and everything else at least has some of those traits bred in as well. I would agree with Marla's concept of a hive which survives for at least 18 months as a minimum benchmark but a any treatment would nix the label of survivor stock. I get calls all the time about bees that are "survivor" stock because they are in a location for years but most when investigated show evidence of "breaks" in brood comb telling me likely it is a hive which was repopulated annualy by swarms. I look for those little dark bees (maybe the little is evidence of small cell) which normally seem to have smaller but somewhat aggressive stock and are visibly different from the norm. Those in the wild, with anecdotal support, I would call survivor stock.