Why do people think that our economy is thriving, when the stock market is propped up by a 16% tax cut, and the 4% unemployment does not show any more purchasing power, as proven by the lack of inflation?

Why do people think that our economy is thriving, when the stock market is propped up by a 16% tax cut, and the 4% unemployment does not show any more purchasing power, as proven by the lack of inflation?