First of all, I am quite familiar with what goes into a saltwater tank. I managed a pretty large fish dept for almost a decade. We stocked an equal amount of both fresh and marine fish as well as a substantial amount of coral and inverts. I have, myself, kept sw in my own home.
I also find things in my tanks that I have never seen before. For instance, I have 3 different species of unwanted pest snail in my tanks atm, which seemingly appeared out of nowhere.
I also experiment a lot with various semi-terrestrial mosses to see what I can get to grow immersed and how the immersion effects the plant growth. I've done Co2 and no Co2, ferts and no ferts, high light and low light. Recently, just for kicks, I let the plants grow until there was no more room in the tank. It went from trimmed to what you see below in about 2 weeks.
I'm not here to dissuade anyone from going saltwater if they've got the cash and inclination. Saltwater fish can be quite lovely. This is fishkeeping and its every person's own personal journey. I just thought it a bit distasteful to see a thread solely for the purpose of bragging like you'd somehow 'stolen a customer away'.
In regard to the aquarium being the natural breeding environment for most fish, most real breeders source their breeding stock from the wild.