The value of items they donate to charity is deducted from their taxable income, it is not deducted from the taxes that are due.
If a company's gross taxable income is $100,000 and they donated inventory valued at $10,000 (that cost $4,000 to make), then their taxable income net of the allowable deduction is $90,000. If they pay 30% in taxes, then their tax burden is $27,000 on that $90,000 instead of what would have been $30,000 for the $100,000, so they saved $3000 on their taxes, BUT it cost them $4000 in production and manufacturing costs for the goods they donated, so they still lose a grand, all told. A business would not ramp up production just to donate the products unless they were seeing a 70%+ profit margin on those products, and once you add in the labor costs and any operating expenses that would go up as a result of producing more goods like administration costs, salaries, plants and equipment, that pretty much never happens. There are many reasons a company might donate goods but I can't imagine a situation where a business would do so as a income-generating activity because it is virtually impossible for a business to end up ahead in terms of making a "profit" on the tax savings.