After World War II the world industrial base was either ruined or tooled up for wartime production. The great U.S. postwar boom lasted from 1945 to 1973, America was factory to the world during these years because it had huge advantages in workforce, industrial base, infrastructure, and money. Today the world has overcapacity in nearly all industries, margins are low, and cost cutting is the obligatory survival strategy.
The mass systems industrial revolution created the huge increases in wealth and wellbeing seen in the 20th century. This revolution began around 1900 when the marriage of science and industry was finally consummated, but it was mostly over by the 1990s. That means that there's minimal primary technological innovation now, so returns to investments in industry and infrastructure are nearly zero. The next industrial revolution is the robot revolution, but it's only just getting started now, all human systems will be transformed, and vast amounts of new wealth will be created in decades to come.
The world has been accumulating huge levels of debt for 25 years, this is debt that cannot possibly be repaid, but the accumulation is still continuing. Most of the world switched from industrial capitalism to financial capitalism (the capitalism of the Medici) in the 1990s with the end of the mass systems industrial revolution; one result is the rapid rise of oligarchies in many countries including the U.S., Russia, and China.