Although bingevader says hobby keepers are not able to make changes, I suspect that if we had direction then we could by virtue of selection of purchases, removal of aggressive queens (& hence drones). Whilst we have beeks such as those who may post on here claiming that we should only have Amxxx then nothing will happen until GM bees are available. Then we will have lovely bees with no genetic variability and vulnerable to every disease going. It is for the knowledgeable and experienced to give good guidance and a clear strategy now before that happens.
Believe it, or not, two-hive owners have quite a lot of bargaining power because of the size of the market. You just have to be clear about what it is you want to buy. The suppliers will listen if you're determined enough.
IMHO, when you buy a queen, you are doing it for two reasons:
1. The quality of her female offspring.
2. The quality of her male offspring.
There is lots of attention paid to the quality of the workers (productive, disease resistant, non-swarming, docile, etc) but this is only part of the picture. The other female caste includes the queens she may produce. If you are buying a queen for less than ~ £50, she will probably be open-mated. So her daughter queens will only carry 50% on average of her genes. The daughter queens female progeny will, therefore, only have 25% on average. Clearly, raising queens from open mated queens is not a very good strategy.
It may not be immediately obvious, but, the quality of the drones is where you can most impact the quality of bees in your area. The drone has no father so 100% of his genetic material (16 chromosomes) comes from his mother. If all the beekeepers in an area can agree on what they want and flood the area with sister queens of a given line, they should be able to have a significant effect on the drones that virgin queens mate with, and hence the quality of the next generation daughters. This is called "drone flooding" and is one of the techniques employed by commercial queen rearers. Small scale beekeepers can do the same thing, but, you do have to get everyone to agree to follow the same strategy. Not only that, you have to keep doing it year after year. Gradually, you will see an improvement - BUT - a plan is only as strong as it's weakest link and if one member decides to do their own thing, you are all wasting your time.