[noahc]

It seems plausible to make it so that people can't become corporations.

1. The IRS already does this with certain classes of businesses in which they make it illegal to form them purely for tax avoidance purposes.

2.You set the corporate income tax to 0, but personal income tax to whatever. You then make all corporate profits flow through to individuals, and make corporate write offs and deductions rare/impossible/non-existant.

Under our current tax environment, you're right. But there is nothing inherent in reality that makes this impossible.