Auguste Escoffier, in his turn of the 20th-Century cookbook, extolled the virtues of using pure starches (corn, potato, rice, etc.) for their superior thickening qualities ... and then went on to use flour-roux in all of the recipes in the book.
Most of my cream soups are thick and I use the cream to thin them out ... but when I need to thicken something - I just use a flour roux. Well, with the exception of chili and I'll use masa flour.
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain