What do you think we are spraying when we spray for mosquitos? Of course it is to help the little flying pests turn Christians gay. Really. Have you ever seen the mosquito population actually go down? Do you really know what is in that spray? You just assumed, and now you too are gay.
You can already return complex data structures using jsonagg and recursive queries. I can see wanting to make that easier and more intuitive to do. Current sql does not restrict you to just 2D table data structures though.