Government should be efficient, but I agree without a profit motive it is an unrealistic expectation.

Efficiency does not correlate to what a government does or how much it spends.

It is tied to whether the spending is achieving good value for the money. As a taxpayer, I would much rather see government build two miles of highway for the same money as one mile of highway if both are of equal quality. I would prefer to see the government spend money to provide more housing to the poor than less of equal quality for the same expenditure.

I think you are confusing efficiency with issues like balanced budgets. Your response is focused on the roles of monetary and fiscal policies on the economy, which is a different discussion.

Government deficits are not a measure of "efficiency" they are measure of both fiscal stimulus (your point) but when not needed but engaged in due to a failure to constrain spending a reflection of lack of fiscal control (as evidenced by the inflation set off by our government in the US when it poured money into a supply constrained economy).

Government could accomplish all the monetary goals you outline without competing with the private sector for goods and services by increasing or decreasing the amount of currency in the system. That was essentially what happened under some of Bernanke's quantitative currency strategies.