I suspect this is because there is no good answer. The economy moves further and further out of control. Personal borrowing becomes unserviceable and asset prices move up so encouraging unrealistic speculation. The economy moves towards a severe crash. In the declining economy interest rates are maintained at a rate too high.
Demand remains flat and the people struggle on, locked into a stubborn recession.
So the booming economy booms more, the slow economy slows down further. The inevitable consequence is that the economies move further out of sync. So as time goes on the compromise interest rate becomes less appropriate for both economies.