I think we should advocate for law that would require pet shops workers to get some type of certification. I'm so tire of their dump suggestions. Not only is cruel to the animals but also is consumer fraud!!!
My local petco has tons of bettas in tiny platic bowls with less than two inches of water!!
Since you are the one that is going to be housing this animal for the rest of its life you should be the one to have done your homework before hand and know what your going into. I do agree it would be awesome to have a full staff of trained ichthyologists but when most fish stores pay at or around minimum wage that will never happen.
Yup, it's our responsibility to get online and do our research and then make our choice whether to give our money to the LFS that does things right or continue feeding money into places that make it obvious they don't care. If you can't walk into a store without seeing something objectionable, order your stuff online. It ends up costing about the same if not less.
And don't be afraid to confront about dead fish in the tanks. Bettas are something that upper management will have to figure out by themselves before they actually change things so maybe write a few letters?