The big companies are suffocating entire industries because their scale is so large that they don't even need to profit in many of their businesses. They just enter new markets, snuff out the competition, and add eyeballs to their platforms.
Amazon is a movie studio and a grocery store and a primary healthcare provider.
Google owns every ingress to the web on every pane of glass.
Apple taxes and polices all activity happening on a platform they tightly control and that due to economies of scale you can't launch a competitor. Their duopoly partner in crime is complicit.