Ask Lemmy

A few reasons:

1. States are not currency sovereigns in that they do not create and control their own currency. All the money the state uses come from revenues they collect in taxes, fees, sales, etc. This is not the case for a national government, which creates all the money it needs for whatever it wants to spend money on. This gives the national government a lot more spending power than any state could possibly have, regardless of the state's GDP.

More importantly, though,

2. All states except Vermont have statutory or (state) constitutional requirements to have a balanced budget every year. This means they cannot run a budget surplus or deficit. Any surplus has to be spent or returned to taxpayers and any deficit needs to be resolved that year. This makes it incredibly difficult to run large programs like a M4A over time. When the state runs into a budget shortfall, the M4A system would be the first on the chopping block.

3. Insurance companies fight HARD against anything that hurts their business. This is specifically why Obamacare (the ACA) didn't include a public option despite Obama campaigning hard for a public option in the 2008 election. Insurance companies got their stooges in the Democratic Party to kill the public option when the ACA debates were going through Congress. They do the same in states when states try to do something about the healthcare industry. And if insurance companies publicly talk about a proposed bill causing them to raise rates or pull out of a market, that's a huge political stick to swing.