That's why I attacked it by submitting a complaint, which I've heard Petco takes very seriously. The store where I bought the fish had very well-maintained facilities and nice, clean cups for their bettas. There were two that were dirty, but they were set to the side of the sink and were clearly going to be getting a water change.
Also, a semi-acquaintance who used to work at a Walmart told me that they would actually get reimbursed for the dead fish, so it didn't make a difference if someone bought them or if they died. Not sure how true it was, because she wasn't always 100% honest about stuff, but I would imagine that's partially true. I work at my mom's feed store (no fish, sadly), and we order baby chicks from a hatchery. If we have several from one shipment that die during shipment or shortly after arriving, they replace them all. They probably would for smaller numbers, too, but it's not worth the time to do so; so I'd assume there's something similar in place for fish hatcheries, though I can't say for sure.
If people weren't buying the fishes due to expressed concern over their often poor care, there would be no need for suppliers to reimburse the store for lost fish.
A cup,bowl,vase,or aquarium can have crystal clear water but still contain levels of toxins (ie) ammonia,and nitrites. Without a biological,mature filter, (cycled)the fishes are subjected to swimming,laying,in their own excrement between water changes.
If there is no filter in betta enviornment to process the waste, and or ammonia from chloramines in water at water changes ,,,(most water contains either chlorine ,more often chloramines) then proper dechlorinator and frequent (perhaps daily) water changes are mandatory.
These fish are shipped in stressed conditions,often kept in stressed conditions,frequently removed from their containers (stress),frequently over medicated due to fact that most meds call for dosages per gal, (stress)over fed in small volumes of water which lead to toxins accumulating in small enviornments, (stress)kept in unheated tanks or at temps to low (stress),water not changed frequently enough in unfiltered small enviorments, (stress) often purchased sick due to above mentioned ,and often selected for their colors rather than searching for healthy specimens.
This is why the majority of these fish die, and why this forum as well as many others ,have all too many posts concerning sick ,slowly dieing fish.
When folks begin to grasp that these are tropical fish that need the same things all tropical fish need, then far fewer of these fish will suffer.
Fishes,,(all fishes) could care less whether you love them, or give them names ,or attempt to attach humanistic qualities to them.
All they want,need,is proper enviornment,proper foods, and proper care.
ALL BETTAS will fair much better in heated ,filtered,cycled tanks of at least five gal per betta despite what those who feel differently may suggest.
If you truly love your Bettas, and at some point begin to tire of replacing dead fish and or attempting to medicate them ,then perhaps what I am saying will give you and others pause to consider perhaps a different approach to their care which may surprise many.