What Ever Happened to the Milkman?

I can remember the milkman coming at least into the early 60s. If i remember right the company was Sealtest Dairy. We had a big silver insulated box by the back door where milk and other dairy items were placed. I can remember getting cottage cheese in aluminum tumblers that were a different color every week. My parents still used those tumblers for drinks up until the last time I was there in the mid 80s.