Some of the betta species I keep are essentially nearly extinct in the wild. This is not due to capture for the aquarium trade but is rather the result of habitat destruction.
Without hobbyist breeding programs, these species would most likely disappear for good.
While I do not agree with some of the practices used to obtain wild-caught stock, in some cases life in an aquarium is better than slow extinction.
Also I'm sure if my fish were so unhappy they wouldn't be spawning as frequently as they do. I have a few wild-caught species and they have adapted very well to life in my tanks.