Will keep this short.

1) Its not Government spending (even though Gov spending is needed in the beginning to get the dollars into the economy (private sector) that essentially needed. Its DEFICITS. How you get to deficits, is a matter of discussion where we can have some good logical debates. But what we cannot debate about (because of the accounting identity fact) is that the government deficit is equal to the private sector savings. Both sectors cannot run a surplus, its impossible (unless the foreign sector is running a deficit, but for the US, it is not)

2) are central banks more powerful than markets? -- Yes
If ECB wanted right now, it could lower all EZ nations' bond yields to 1%. However, that is unlikely given Germany's unwarranted stance on inflation and their ability to politically control the ECB. However, thats another issue, one that does not pertain to the operational realities of the monetary system.
Same would go with the FED/BoJ. They could keep rates at 1% forever (10 year yield). However, there are consequences to that. Once the economy normalizes, inflation will pick up, thus the FED will be forced to raise rates (because of rising inflation, NOT markets)

You brought up Nat Gas/oil. Imagine a nat gas producer who could produce (read "print") Nat Gas at the press of a button (read "keystroke) [Lets assume He would be the only one in the world, because there is truly only 1 issuer per currency].
He could keep Nat Gas prices at whatever price (lets say 50 cents) forever by just producing NatGas with the push of a button right?
But obviously there would be "trade-offs". He would be selling NatGas at a cheaper rate than what he could. He keeps it low for now to get people to convert to Nat Gas. Once people start switching to NatGas, he would then be forced to raise prices so he would stay in business (because lets assume $4 is the breakeven point...That breakeven point for inflation is more complex than this simple scenario, but you get my point).

The Same goes for the FED. They can keep Rates as low as they want forever, however, there will be inflation costs later which they would need to combat by raising rates.

3) I read ur post, no need to re-explain here...but I disagree with some of your analysis. Again, as long as Japan (the BoJ) can issue Yen, there will be NO crisis (barring exogenous events).

To conclude:
In the end, all that matters is if they can issue currency or not. Yes, there is CONSTRAINTS (inflation), but that is more of a complex issue then just "monetary" reasons.
Enjoyed the debate Sir.