More and more it seems to me the economy operates under a group of economic constraints, and performs to the level of the “worst” of these constraints.
Credit, housing volume, business investment, commercial real estate, Collateral worthiness, consumer demand, business confidence, foreign demand, relative energy prices – the list of possible constraints on current economic growth is long and varied.
Of course, some of the constraints are more important than others, and have a larger impact. However, the important impact is they act as a constraint, and not as some additive or multiplicative factor to the economy. It’s as though the economy shambles along as well as it can until it runs into some sort of road block and then that is as fast as it will grow.