Wealth is absolutely a fixed size pie. Scarcity of resources is the fundamental problem that economics tries to solve.
You are applying 19th century economics to the 21st century. Five of the biggest corporations in America are Apple, Google, Microsoft, Amazon, and Facebook. None of them rely on coal or iron ore. They rely on human ingenuity and intellectual property, neither of which is inherently limited.
1. Legal expenses, which are a one time cost
I incorporated on-line for $200. I spent $0 on legal fees.
2. Double taxation, which my plan would eliminate
Most corps in America are S-Corps, which are not subject to double taxation.