It seems to me, from reading this topic before it was edited and afterwards, this is very "human-centric" :

"Assuming a “Young Adult” (assume any age) Tax Payer with many more years of various taxable incomes has satisfied (a) Dollar Limitation (b) Investment Limitation & (c) Taxable Income Limitation, and has the Sch C business which is highly profitable. Please feel free to assume and use any income amounts for current and future years needed to clarify the matter."

What you have skimmed over twice is, does the use of this vehicle meet the regulation qualifications for that business as required?

Because you focused on the person, their income, the costs, etc. You didn't really focus on the Business. Taking section 179 or Regular depreciation or even the Mileage Allowance are all options that you evaluate for the relationship of that vehicle and that business and what is tax advantageous for that vehicle and that business.