"If a species as a whole doesn't survive well in captivity, it should not be collected."
Well........That would preclude a good deal of the fish seen in LFS, as MOST will be dead within a year. I do understand the RESPONSIBILTY of the buyer to provide the proper conditions for captive husbandry, but if we followed your above advice nobody would be keeping Acropora today, as 15 years ago NOBODY could keep one alive.
Things change when people learn the specific needs of animals in captivity.
If I am willing to provide the proper environment for keeping a Princess parrotfish.....................I don't want YOU or anyone else telling me I can't have one.
BTW, I also have a Heteractis crispa (7+ years) a H. magnifica (2 years), a Powder Blue tang ( 2 years ), and 10 Anthias ( Squareblock and Bartletts).........Most of these fish would not be imported if we went by the idea that they do poorly in captivity and should not be offered to hobbyists.
Now, I know as well as anybody that a whole bunch of people keeping reef tanks do NOT provide the proper care for their animals, but that is why we have BBs like this one..........to educate those willing to learn and try new things.
John