If you eliminate deductions, you end up with a gross receipts tax rather than an income/profit tax system.

There’s nothing at all simple about switching from one to the other. (Grocery stores in particular would be extremely hard-hit and a lot of us rely on them to survive. The wheels would come off quickly if not carefully thought though.)

Grocery stores would raise prices. What is the issue?

If the issue is it affecting poorer people adversely, then that should be addressed by making them less poor, e.g. the government giving them money.

Grocery chains that were more vertically integrated would handily outcompete independent grocers who had more intermediate steps in their supply chain, each of which was taxed on their B2B revenue.

Whole Foods could conceivably become the equivalent of a discount grocery by virtue of such integration, after Amazon bought up farms and distribution channels.

This is also why a VAT is theoretically better than a sales tax, in my opinion: it removes the incentive to vertically integrate to avoid the transaction tax....

That’s a good point I had not considered.

> Simply eliminate deductions and credits and exemptions.

Simply? In a global world economy? There is nothing simple about it.