It has been a long time since developed nations have tasted serious inflation. Unless you are near 60 or older you will not have experienced the last time inflation was a serious issue in the 1970s into the early 1980s.
Coupled with low inflation is low interest rates. It is hard to miss the pattern of interest rates since 1982. Each increase in interest rates was followed by a new low in interest rates until we bumped against zero and stayed there for much of the past decade.
The stock market loves low interest rates. The constantly declining interest rates gave us a stock market that has relentlessly climbed. In the early 1980s the price/earnings (p/e) ratio for large capitalization stocks was in the single digits and the dividend yield was in the 6% vicinity. Now the p/e multiple is closer to 30 and the dividend yield is below 2%.