Coincidentally, and as another pre-1.0 fart myself :-) -- one who remembers when Ted Nelson's "Computer Lib / Dream Machines" was still just a wild hope -- I was thinking of something similar the other day (not USPS-specific for hosting, but I like that).
It was sparked by going to a video conference "Hyperlocal Heroes: Building Community Knowledge in the Digital Age" hosted by New_ Public:
https://newpublic.org/
"Reimagine social media: We are researchers, engineers, designers, and community leaders working together to explore creating digital public spaces where people can thrive and connect."
A not-insignificant amount of time in that one-hour teleconference was spent related to funding models for local social media and local reporting.
Afterwards, I got to thinking. The USA spent literally trillions of dollars on the (so-many-problematical-things-about-it-I-better-stop-now) Iraq war.
https://en.wikipedia.org/wiki/Financial_cost_of_the_Iraq_War
"According to a Congressional Budget Office (CBO) report published in October 2007, the US wars in Iraq and Afghanistan could cost taxpayers a total of $2.4 trillion by 2017 including interest."
Or, from a different direction, the USA spends about US$200 billion per year on mostly-billboard-free roads:
https://www.urban.org/policy-centers/cross-center-initiative...
"In 2021, state and local governments provided three-quarters of highway and road funding ($154 billion) and federal transfers accounted for $52 billion (25 percent)."
That's about US$700 per person per year on US roads.
So, clearly huge amounts of money are available in the USA if enough people think something is important. Imagine if a similar amount of money went to funding exactly what you outlined -- a free web presence for distributed social media -- with an infrastructure funded by tax dollars instead of advertisements. Isn't a healthy social media system essential to 21st century online democracy with public town squares?
And frankly such a distributed social media ecosystem in the USA might be possible for at most a tenth of what roads cost, like perhaps US$70 per person per year (or US$20 billion per year)?
Yes, there are all sorts of privacy and free speech issues to work through -- but it is not like we don't have those all now with the advertiser-funded social media systems we have. So, it is not clear to me that such a system would be immensely worse than what we have.
But what do I know? :-) Here was a previous big government suggestion be me from 2010 -- also mostly ignored (until now 15 years later the USA is in political crisis over supply chain dependency and still isn't doing anything very related to it yet):
"Build 21000 flexible fabrication facilities across the USA"
https://web.archive.org/web/20100708160738/http://pcast.idea...
"Being able to make things is an important part of prosperity, but that capability (and related confidence) has been slipping away in the USA. The USA needs more large neighborhood shops with a lot of flexible machine tools. The US government should fund the construction of 21,000 flexible fabrication facilities across the USA at a cost of US$50 billion, places where any American can go to learn about and use CNC equipment like mills and lathes and a variety of other advanced tools and processes including biotech ones. That is one for every town and county in the USA. These shops might be seen as public extensions of local schools, essentially turning the shops of public schools into more like a public library of tools. This project is essential to US national security, to provide a technologically literate populace who has learned about post-scarcity technology in a hands-on way. The greatest challenge our society faces right now is post-scarcity technology (like robots, AI, nanotech, biotech, etc.) in the hands of people still obsessed with fighting over scarcity (whether in big organizations or in small groups). This project would help educate our entire society about the potential of these technologies to produce abundance for all."