Are 20-30% of your prices due to taxes (not including your employee's taxes)?
No. My companies income is a mix of about 75% labor and 25% product sales. If I didn't have to pay the 'employer' portion of the Federal taxes, I could drop the price I charge customers for labor. The prices of hard goods sold would also drop, as my suppliers dropped their prices. My company's customer base is 99% companies and very few individuals.