washing machine with washing powder dispenser

Today’s idea.

Why don’t washing machines have big resevoirs for washing liquid or powder, fabric softner and whitner/bleach?

You would fill it up and then the washing machine would automatically dispense the various washing liquids or powders into the wash. no more messing around with all those cartons of washing powder, bottles of softner and tubs of nappysan. It would alert you when it runs out (perhaps via email so you can pick some up on your way home).