What does mainstream economics tells us about low interest rates?

 Mainstream economics meets the Euler conditions so this chart is an impulse response dissipating from the system, going back to neutral. 

Neutral will be a very long period of a half point deflation. The central bank, due to double entry accounting and the Euler condition, will extract an amount equal to its currency risk until neutrality is reached.

That is the meaning of mainstream, Newton's grammar holds. How many economists think the economy will tolerate a half point deflation over a very long period? The mainstream violates because this chart needs a larger market size then available.  It requires much more price granularity then the economy can deliver, so we are not going out to any necessary infinity. Our binomial is too sparse to approximate a normal distribution to sufficient accuracy.