If it's information, you don't need the Post Office. Letters, bills, checks, photographs, movies, newspapers, magazines, books are all pure information: modern technology can push all of those through the glass fiber to my house.
That leaves stuff that has a physical form. FedEX. Big Brown. Amazon Prime comes to mind. Unlimited free two-day. One day for $3.99 / item.
Right now, the Post Office subsists on revenue from junk mail (physical spam). That's not going to last. If it wants to remain relevant, it has to outdo the other carriers in the physical delivery of stuff I want.
Generally incorrect. You may not want information delivered to you in physical form, but there are still many people who do, and are willing to pay for it. That's business.
Currently, the ability to operate depends primarily on revenue from 1st class letters, not the "physical spam" as you have stated. That base is shrinking fast, and is why the USPS has been trying to get Congress to allow necessary changes.
Lastly, the USPS destroys UPS and FedEX in the cost to deliver the smaller sized items. Generally, the USPS gets it there as fast or faster, safer, and for less money. On larger items UPS and FedEX have the edge. This is supported in many independent studies, usually done around the holidays.
According to the July numbers, first class is about half the revenue, but is on the decline, along with periodicals. Junk and packages are on the increase.
Once you've tried automatic bill-pay, you never go back to writing checks and licking stamps.