If you were an accountant, you'd realize that income and expenses can be legally moved from one year to another. (just like paying my property tax on Dec. 27th, rather than Jan 15th to adjust this years personal taxes for myself)
Throw in depreciation, loans, financing of purchases, accounts receivable, etc., and it gets messy...

The IRS will first look at the return, make sure that is self-consistent. (A task in itself)

Then on an audit they'll possibly look that the person's net assets increased by about the amount that they have as income.
If it's a reasonable match, the IRS will be satisfied.
(And despite your allegations, the IRS could be quite satisfied with such a return.)

But would it be correct to say that if you look at several years of return you will get a reasonably accurate depication of income over that time? In other words, are you just shifting the income and expenses from year to year to reduce your taxes?