It's because there is a market for them. They won't be back if there's no market for them but due to those investors that are eyeing them and thinking that they can profit from them, they come back. There's no solution for that but the investors will eventually have to turn away from them when it's no longer profitable and for the side of these project makers, they'll just revert the attention of their investors by doing some updates or making a new project that will look interested to the same investors that they've got.