The truth is that most of us don't like to think of the big picture. If you spend anytime at an LFS unpacking new fish shipments you quickly realize that a 20% death rate in shipping is common on average. Add to that another 10% or so inn the first 24 hours and a third of all fish die before someone even gets a chance to take them home and put them in their tank.
But wait! It gets worse. The shipments that go to your LFS first went through a distributor where they arrived from a very long trip from where they were collected. The death rate in these is at least as high since many of the fish are stressed for longer periods, were subject to bad collecting procedures, etc -- and this is thousands of fish a week going to distributors.
But wait! It gets worse. First they had to be collected and sent to holding locations from the original wholesalers. Often these are facilities with sub-optimal holding pools with thousands and thousands of fish. Many have diseases which spread, infect and kill before they leave the facility.
So the question is what percentage of fish die in transit before we put them in our tanks? There was a study on this a number of years ago, and it's more than a little horrifying. I'm sure someone here has the link.
It's one of the reasons that sustainability is the cornerstone of this club, and the reason many are passionate about not contributing any further to the death rate by ignoring best practices.