why no USA cyberfinance infrastructure?

[mellowtigger]

After a recent discussion with brian_bogue about costs of online transactions, I have to wonder publicly a question that I've pondered before:

Why doesn't the USA provide infrastructure for the online economy?

The USA for the last 2 centuries has provided infrastructure for physical money. It performed the costly services of minting coins and printing bills, even vaults and security for storing gold-backed money, so why doesn't it provide the online equivalent? No, I absolutely do not mean selecting a favored cybercurrency. I mean providing the network and database to process microtransactions, providing the bare minimum necessary to maintain a financial system. Why should they? Using a credit/debit card includes notoriously high fees even on tiny transactions. That's profit, sure, but it's profit to some corporation siphoning its benefits from the currency of the nation. This non-cash issue came to the foreground of some news stories during the start of the pandemic, when some businesses decided to not accept cash, since it was thought to be a potential vector for virus transmission.

The currency of the nation seems to be the national government's responsibility, right? I've tried to read up on the Constitution's wording, but clearly I'm not the first to be confused by its vagueness.

My argument is this: The USA federal government is responsible for the creation of durable (enduring frequent transaction between citizens and corporations) money. In the modern age, that transaction is digital, so the USA federal government should be responsible for creating that enduring methodology, and that means providing a "currency network" of servers and databases which people may access "for free" (paid by taxes) with the same ease and zero-transaction-cost of using physical money.

So... does anyone know why we don't do that? It seems obvious to me that we should.