I know someone who works for the post office. She tells me that Amazon has definitely resulted in an increase in both revenue and mail volume for the postal service.
BUT the increased revenue is not enough to keep pace with the increasing demands for labor to handle it. For example, she showed me a picture of a post office backroom that was stacked to the ceiling with cases of toilet paper. Large numbers of people now apparently order their toilet paper by the case from Amazon and have it delivered buy the postal service.
Nobody ever made provisions for the increased labor the postal service would need to start moving pallets of toilet paper.
I honestly have never thought of ordering toilet paper from Amazon. I’ve ordered a lot of things, including a rocker/recliner chair - the savings on delivery on that alone probably paid for my Amazon Prime membership - but I could see where a lot of TP orders would be hard to keep up on.