Entrepreneurs like Mark Zuckerberg of Facebook and Elon Musk of Space X have taken risks: Business Assignment, PSB, Singapore

Questions
Entrepreneurs like Mark Zuckerberg of Facebook and Elon Musk of Space X have taken risks to build to their businesses and been successful at it. The fundamental premise for their success mostly hinges on the ownership of private property and free market forces.

For billionaires like them who have made their wealth mostly based on their own effort and perseverance, would it be fair to impose high income tax on them to redistribute their wealth to help the poor?