Yes, many people in the hobby still stick with a variety of frozen foods and a guesswork of supplements. This is because at one point that was the best option, there were no prepared foods proven to be sufficient for the long term nutrition of marine fish. But nutrition is too important to leave to the guesswork of a hobbyist untrained in animal nutrition and a hodgepodge of supplements. Leave it to professionals. At least one prepared food has proven to be all that is needed to properly feed marine fish (including moorish idols, lionfish, tangs, angels, mandarins, triggers, clowns, wrasses, etc.).
Yes, many fish are captive bred, but even within the species that are captive bred most individuals in the hobby are wild caught. 'Close to breeding yellow tangs' doesn't mean anything except we still don't even know how to breed most fish.
My personal opinion is that if you haven't tried both methods (variety of frozen foods and high quality pellets exclusively) you really can't say anything beyond 'the food I feed is at least good enough to keep them alive for years'. Experience in one type doesn't disprove the other.