I'm not sure who decided having a citizenry of idiots was a good idea, perhaps it was the lawyers, maybe it was the politicians. When you want to know why the market for something grows, you need to look for the incentives or disincentives. In the case of stupidity, it's growing steadily - but why?
Lawyers make it profitable by suing companies because they failed to tell you not to do something incredibly stupid with their product, for example - using your rotary mower as a hedge trimmer.
Health care has lowered the risk of doing something stupid by getting to the point where they can fix things that stupid people do to them selves.
Politicians incentivise stupidity by offering free money to lazy people.
So what's the down side to stupidity? At the moment, it would seem there is almost none. It's profitable, it's easy, and the risks are very low. Don't expect a market like that to do anything except grow.