Friedrich Ruttner on the importance of ruthless selection
I recently came across a book containing a passage that supplies authorative support for the thesis that failure to select for health is resulting in widespread ill health in bees, and that treatments are very much a feature of that problem. You have to join up the dots yourself, but what the book, published by the top bee breeders association in the UK is saying is: widespread treatment will inevitably result in widespread health failure. I've copied the relevant part, and offer it here for use in any way people see fit.
Best to All,
Friedrich Ruttner, Breeding Techniques and Selection for Breeding of the Honeybee, translated by Ashleigh and Eric Milner 
Chapter II: Selection for Performance
1. What is breeding?
Queen breeding is, in the first place, simply the increase in the number of queens. By regular rejuvenation and keeping a reserve supply of queens the output of an apiary can be very substantially increased. The enhanced productive energy of the young queens is utilized and deficiencies in the working stock, which result in queenlessness, drone laying, or any other kind of failure in a queen, are made good. Queen breeding ranks as the most important activity in the management of an apiary; by it the apiarist, in the words of Professor Shillers of Vienna, advances from being a beekeeper to being a bee breeder.
Yet breeding is not merely a question of reproduction. Above all, breeding implies improvement in the bee's performance capability. No colony is exactly like another; brood rearing, inclination to swarm, foraging vigour, stinginess, susceptibility to disease, differ from colony to colony. Breeding means the augmentation of the best [the positive variants] and the ELIMINATION OF THE BAD [the negative variants].  The aim is the attainment of an apiary which is uniform and has an above average performance.
Breeding is by no means a human invention. Nature, which in millions of years has bought forth this immense diversity of wonderfully adapted creatures, is the greatest breeder. It is from her that the present day breeder learnt how it must be done, excessive production and then ruthless selection, permitting only the most suitable to survive and eliminating the inferior. If this harsh rule of nature is either set aside or relaxed the constraints will within a short time be broken through, and a species will disintegrate into a large number of different forms which through divergent colouring and living requirements, through unusual body forms, will depart from the natural pattern. In laboratory animals which are kept only for study and not within a definite breeding objective, these phenomena can be regularly observed. At the same time, reduced fitness for life under natural conditions very quickly results, because in nature this is only preserved by incessant and rigourous selection. If this selection is lacking because the trouble of finding food and warm shelter and taking care of the young has been removed and protection from enemies has been provided, the ability to hold its own in nature gradually but inevitably declines. What has the wolf, the ancestor of our dogs, turned into during the course of millennia under the hand of man? A Dachshund or Poodle would soon be a pitiful wreck if it had to try to exist on its own.
Nature is also the breeder's greatest instructress as to how to avoid inbreeding:- no mating within the same colony; mating flights to far distant assembly places; multiple mating.
2. The Breeding of Honeybees
Our bees have certainly not yet reached the condition of the domestic animals just mentioned since even today they still have to maintain the struggle for existence largely on their own. Nonetheless, we have gone a very long way towards making their lives easier, so that the laziest colony or the latest swarm is not in danger of starving the following winter. Today the majority of beekeepers restrict themselves to protecting their bees, but allow them to increase just as they like. What is the result? Stocks with excessive swarming tendency grow ever more numerous, while the good foragers with weak tendency to increase, which rejuvenate themselves by supercedure, are driven back Wit the Heather bee, and in the Carinthian method of breeding for swarms which produce bees quite useless for a modern beekeeping business, we see the result of these practices quite clearly.
 Published by the British Isles Bee Breeders Association [BIBBA] by Arrangement with Ehrenwirth Verlag, Munich;1988, pages 45-46
 This sentence is italicized in the book.
The race isn't always to the swift, nor the fight to the strong, but that's the way to bet