My total guess is weighing scales used to be expensive / inaccessible for the common home baker and one of the first popular recipe books thus used volume, became wildly popular, and indirectly taught a generation of home bakers that baking recipes are by volume, not weight.
I wanted to believe my opinion is popular yet recipes I’ve seen are almost in volume and I don’t know why.
Baking is chemistry for sure.
My total guess is weighing scales used to be expensive / inaccessible for the common home baker and one of the first popular recipe books thus used volume, became wildly popular, and indirectly taught a generation of home bakers that baking recipes are by volume, not weight.