Alex,
Discoloration stains can be removed with the right treatment. A frontloader with a heater and a good detergent is the best way to get rid of them. Oxygen bleach plays an important role in that. But on my trips across the big pond I had good results getting dirty socks clean too in a Kenmore belt drive toploader and Tide with bleach. Perhaps you are happy with getting not all the stains out of your laundry, but personally I can't stand laundry that doesn't come totally clean.