Real estate cash flow vs Physician/Doctor cash flow. Difference?

[Bryan Tasumi]

Real estate cash flow vs Physician/Doctor cash flow. How many houses and how much time would it take a real estate investor to get enough cash flow to equal that of a doctor making 300k + benefits a year? 

I am assuming it is much easier for a doctor to buy rental properties and scale up to a 300k cash flow from investment properties than a full-time real estate investor starting off with 100k cash?