I don't feel that copperbands or mandarins are hard fish to keep. Like all fish you should not buy one if you don't know how to feed them. They live as long as most fish if you do a little research. Moorish idols are a different story and are considered difficult. I have had many of them and none for more than five years.
But copperbands and mandarins are fairly easy. If you are the type of person who buys a fish and feeds it flakes and pellets, there is an entire assortment of creatures that you will not be able to keep. Instead of raising the price, the LFSs should inform people how to keep that animal before they sell it to you. We all know that isn't going to happen because they are not in business to teach, they are in business to stay in business and if people keep buying mandarins and copperbands and kep trying to feed them flakes, pellets and seaweeds, the LFS will make a nice profit and it will be good for them. Unfortunately, not so for the fish.
Almost all the fish we keep should live at least ten years, even copperbands and mandarins. The only fish with a shorter lifespan are smaller fish like clown gobies, pipefish, seahorses and manta rays. Unless of course you have a large enough tank.