I don't agree that those tools can only make trivial games. Not GameMaker, at least. I've seen several very impressive project, when I was younger and played with it a lot.
Ther are some indie game devs who make quite good games with game maker. Good enough that they sell well enough to make a living from it or at least some income.
Casual games? Most likely yes, but not every gamer is hardcore. There are a lot of people who like some easy entertainment, but don't want to invest a lot of time to learn a game, train their reactions, wade through equipement/item catalogs, consult web sites with calculators and optimizers ... but - just want to be entertained for a while.
Game Maker is IMO a good tool to make games which are just that - entertaining passtimes. And I want to avoid any negative connotation with that. It's IMO what games have always been about, and is maybe more "core" to a game than anything else.