We live in historically different financial times in the sense of the cost of money, in which, before the financial crisis of 2008, the cost of money that is the interest cost of loans for mortgages, for personal loans, for brokerage margin loans, and for business loans, was appreciably higher than it is today. On one hand, that sounds great, for the cost of money makes a big difference as to whether a particular business investment or its equivalency on a personal level, makes financial sense, and all things being equal it is far easier to pay back a loan at 1.75% than at 10.75%. This would imply that a low interest rate environment should increase business investment, which should, in kind, increase business activity and thereby heat up the economy with higher growth.
In point of fact, America has not had growth greater than 3% since 2005, indicating without a doubt that low interest rates, in and of itself does not increase economic growth. In addition, to the fact that America has suffered through a low growth atmosphere for over a decade, it has also had very low inflation in which the last time inflation was 2% or higher was in 2012, of which the Federal Reserve believes that an inflation rate of 2% is necessary for steady economic growth and for full employment, of which, their biggest fear, is outright deflation, for when products get cheaper by the month, than the economy can quickly devolve into not just a recession but a depression, because people and businesses are less inclined to purchase things now, since they can thereby purchase them later, at a cheaper price.
The fact that inflation is low indicates that low interest rates, which should be adding liquidity and higher purchasing capacity, somehow does not. This then means that low interest rates does not necessarily produce either a higher growth rate, nor does it necessarily produce a higher inflation rate, even though these lower interest rates, surely makes it easier to those in debt to manage their debt, since their corresponding interest payments have been reduced by lower interest rates on things such as: mortgages, car loans, business loans, and even credit card debts, but since economic growth remains low, this implies that within America, there is a significant amount of debt, that despite lower interest rates, cannot ever be successfully managed or discharged.
In addition, how money and where money is issued in the first place, makes an appreciable difference to the economy in whole, that is to say, if money is given directly to those that are struggling the most, they will spend it, because they lack ready money in the first place. On the other hand, if loans are provided at incredibly cheap rates to mega-corporations and individuals that have stellar credit ratings, that money, might trickle down to those of lower socioeconomic levels, but has a strong tendency with all of that great wealth of cash available, to not so much be invested in the growth of America, proper, but will be speculated in worldwide stock and equity markets, for if it costs less than 2% to borrow, there is a strong tendency to passively make money through such equity markets with well managed risk, rather than to invest in factories and labor domestically, especially when the perception is that the people in whole, while having the desire to purchase, don't have the money or loan capacity to do so.