Re: bottled milk to doorsteps in every residential neighbourhood. That dates the research back at least 50 years, I fathom.

I thought door to door delivery of bottled milk disappeared everywhere, driven by the same economic pressures.

Guess you don't have "Milk Stores" in England, huh?

Milk stores replaced door to door delivery in every neighborhood I know of.

Glass milk bottles disappeared at the same time, replaced by cardboard cartons and plastic jugs.

Lugging jugs of "Jug Milk" from the corner store to the front door is the delivery system in every place where I have lived or visited, and it has been for decades.

They're even trying to replace door to door delivery of mail in new subdivisions with outdoor curbside postal boxes serving the entire subdivision.

Of course, the delivery man doesn't get his Christmas bonus at the door anymore.