This would be more meaningful IF the treasuries of the various governments were counting on receiving some steady stream of income from their central banks. Maybe you can point to the lines items in the planned US Federal budgets which indicate this predicted income stream?

Federal Reserve interventions over the past few years have returned tens of billions of dollars per year to the US Treasury, and over $100B per year in 2013 and 2014. Much of this is money circulated out of the Treasury (in the form of interest on Treasury debt owned by the Fed), and then returned as required by law, from the Fed's net income, right back to the Treasury.

In my mind, central bank intervention is, ***in the short term*** (2-10 years), harmless. The harm comes when national legislatures come to regard this intervention, in the form of purchasing "bad debts" from the commercial area, and government bonds as a means of temporary government debt relief, as yet another means to overspend, when overspending is neither wise nor necessary, i.e. in "good times" or "normal times".

This is an excellent reason to keep management of the Central Banks out of the hands of National politics. The central bank managers can cut off their accommodative policies at any time, without fear of political retribution, thus controlling absurd political spending ambitions. (I am referring now to the likes of Rand Paul and others who would like to suck the Fed into their world of fantasy economics.)

That being said, current central bank efforts are the modern version of debt-forgiveness as a way of reducing the blood losses from the femoral artery wound that IS massive public (and private sector) debts. Closing that wound allows economic health to be restored. Eventually, I believe that the Fed will retire the debt it has bought, through a gradual action of forgiveness, but with strings attached as directives to Congress and the President. This is a once in a lifetime opportunity to rebalance national economic policy and give it a chance to again drive on the pavement, instead of on the berm heading toward the ditch. I believe also that this is going through the minds of central bankers around the globe, and it may be done as part of a coordinated action, to give a healthy reset to the global economy.

Time will tell...