My personal opinion is that I think a lot of people get into the hobby with really high expectations and then when those expectations aren't met, they are crushed, demoralized and get out. Just over the past couple of weeks I have had a couple of people PM me telling me that they are just getting into salt and want their tanks to look exactly like mine. That's all fine and wonderful and I'm flattered, but my tank didn't just happen over night. As others have stated here, there was a lot of time and money involved.
It is fine and great to set goals but they have to be realistic and manageable. Really no different than any other hobby or endevour. You can't expect to go to the gym for a couple of weeks and then come out looking like a model (unless you are already a model :P ). Again, time, money and a commitment are requirements.
The hobby is also what you want to make of it. It doesn't cost that much money to have a tank full of salt water, some rocks and a clown clown fish or two. Very low impact on the environment as well. Or you can spend more time and money if you so wish to get some corals and more exotic harder to keep fish. Ultimately the hobbyist has to decide where to draw the line right? Again, too often I see new hobbyist coming in and going full throttle to get that massive nice looking mixed reef with expensive hard to keep corals and fish. That should be something to strive for in the long term, rather than a starting point. That's not what new hobbyists usually want to hear though.
They want to hear how easy it all is.
Anyway, just my humble two pennies.