My daughter graduated in May and is starting her independent life.
I brought her the stack of mail (a major component is Credit Card applications which I remember from the same period of my life) that had accrued at my house over the last two weeks and she looked at it and commented "Why can't they just send emails?".
At 62, I like to get a piece of paper because it won't disappear out of my awareness until I throw it in the trash, and I am missing the skill-set/strategy to have emails have that kind of permanence until I have dealt with them!
Nonetheless, since I use BillPay to pay my bills, I use, on average, maybe one stamp a month for out-going mail and visit the PO maybe once a quarter to ship one of their fixed rate boxes!
So, in my life, what I normally think of as "mail" (out-going) hardly exists. I have also noticed a decrease in junk mail, but that may be partially related to the virus.
It does appear that a major function of the USPS has become an extension of the other package delivery services.
Another factor in the USPS's job description is picking up mail (as needed) from any home every day (yes, UPS and FedEx do it, but not nearly the same scale)!
Looking at this from a macro logistics/efficiency standpoint there is a lot of waste when I see the PO, UPS, Amazon, FedEx, and sometimes, DHL trucks all driving through my neighborhood on a daily basis. I'm not sure it could ever happen because competitors would need to work together, but it would save a lot of time and gas if one service (USPS, since they already have to drive by every house) handled all residential deliveries (with the known contingency that any of the other services could compete if the cost got unreasonable, as is the current model used for USPS already taking some of these deliveries at present).
It is interesting to think about how Amazon's commitment to 2-day delivery has changed the world (well, the US, at least, not sure how prevalent Amazon is in other countries). It certainly is a major component of their success as I weigh waiting 2 days against having to go to Wally World, and combined with the better selection and ease of comparison shopping at Amazon, it is an easy call not to drive anywhere!
But, just as I believe Tesla caused the entire auto industry to accelerate their e-car game (instead of it being a slower transition, likely with lobbyists slowing down regulations, Tesla gave the auto industry an "Oh Sh!t" moment where they realized they needed to get on-board before e-car companies replaced them), Amazon has caused the package delivery services to up their game!