Current tank 3 months.
The 3 year statistic is interesting, to be sure there are many reasons why hobbyists leave, either out of their own choice or a situation arises which prevents them from keeping the setup.
I think a lot of folks don't really know what they are getting into and get put off with the money outlay, maintenance time required, livestock deaths and algae issues, so they bail out sooner or later. I dread to think about the condition of some of these tanks in their final moments. Certainly, some of the stuff I've seen on auction sites is pretty dismal when they are knocking out their complete setup and supply pictures.
It's in a different league to keeping a "regular" pet, for instance a cat. Mine wakes me up at 5am for feeding, pukes over the floor and craps in the toilet to annoy me. But he doesn't come with anything like the stress we are sometimes faced with a reef tank.