Totally true. Much of my cost was because I bought the hardware all new. And because it's big. And some of my livestock and corals costs have been amortized over the years, since I started off with a ten-gallon nano and as stuff grew and I became ever more lustful, the tanks grew. And a lot of people go into reefing and get out of it after awhile because they find upkeep and continuing costs onerous... so there are always great used deals and home-grown coral frags around for sale.
Having said that, though, it drives me nuts when I post a coral for far less than half what it would cost retail, and somebody comes by and wants to knock my price down by half again!