Agree with all except the bulk of the increase in the money supply is not stimulus. The FED had a giant hand in that through their bond repurchase plan and other tools. With the money supply up roughly 30% over the past 12+ months that was not just stimulus checks.What do you mean the US Treasury can't make money with low rates? That is the rate at which they borrow. If the Fed raised rates today the 10 year would go below 0% and invert. The Fed only buys at the short end, they are not buying 10 and 30 years so if the market felt inflation was going to be pervasive there is no forces holding longer maturities down.
The fact is global rates are very low. Go look at rates in Japan and Europe and you will see why it is a great deal for foreign investors to buy in at 1.1%.
The Fed's QE is not inflationary. Everyone said 10 years ago to go buy gold since QE will cause inflation and gold has basically gone nowhere since while inflation has been >2% . There is no correlation between CPI and bond buying. QE does not cause inflation because most of the money stays trapped in the banking system and does not get into the general economy. What causes and increase in inflation is fiscal spending via stimulus, that puts money directly in peoples pockets and they spend it quickly (go look up a chart of M2), hence inflation. You also have to judge the current inflation with the backdrop of a once in lifetime disruption to the supply side coupled with massive fiscal stimulus.
Inflation has been very concentrated thus far in its reach, but I do not believe it will settle down either once supply chain issues are settled. The money supply and inflation historically have held a direct correlation to one another. Not perfectly correlated, but scarily close.