In the 70's it became cool to thicken sauces with reduced cream, emulsified butter, bone marrow and pure starch-virtually anything but mixtures of flour and butter. Roux almost became obsolete and so too did its even easier-to-make (but less stable) sibling beurre manie - typically made by kneading equal volumes of butter and flour together before dispersing it in a hot liquid such as stock.
I don't often thicken sauces at home. But tonight the urge to enrich some chicken stock and use it as a sauce for roast chicken was more than I could endure. The partial result is here in this slide show for your gustation.