These companies voluntarily hire the rabbis. IOW, the rabbis are not robbing anyone, but are providing a service that the companies value.
1. The Companies weigh the cost against the prospects of being labeled "not kosher". They chose to pay.
2. Prices determine costs, not the other way around. Assuming that costs affect prices would result in some very interesting scenarios that simply do nothing to describe the real world.
3. Costs (including taxes) cannot be directly "passed" to the customer through a higher price. Every company sells its products at a price that maximizes TOTAL income. A higher price will push marginal customers into the sub-marginal, reducing the total income to the company.
4. If these companies made an entrepreneurial mistake, then there is room for competition to reap a profit by skipping the bogus rituals. Maybe the blogger would like to put the keyboard down and start a business if they truly believe there is a better way to satisfy peoples' desires.
5. It's not a "tax". If the companies could receive a higher income by rejecting the bogus rituals, the (insert derogatory adjective here) businessmen would insist upon it IMMEDIATELY). This option isn't available when being robbed at badge-point.
"I do not add 'within the limits of the law,' because law is often but the tyrant's will, and always so when it violates the right of an individual."