Uber etc. raise millions and billions in the idea that if they scale enough they can capture a market and monetize it once captured. A market monopoly. Why can

Uber etc. raise millions and billions in the idea that if they scale enough they can capture a market and monetize it once captured. A market monopoly. Why can't industry workers do the same? Once software has eaten the world, what's to stop software people monetizing the employment market they have captured?