Another sad indicator of the March Of 'Progress', whatever that is...
We still have doorstep deliveries ourselves, but I can see it diminishing to nothing in a few years. It costs more, and many households have problems with the milk being left out all day in summer. Paying the milkman can be awkward too, for some (in the old days people used to leave the cash outside, tucked under an empty bottle!).
So another sector of the economy that provides gainful employment for many people goes the way of so many others.
And as a consequence we lose a valuable 'early warning' system which may provide a first alert of a lone elderly person in distress...