Property is generally priced and sold vacant, so a property tax should be based on a fair market value of the real estate + improvements in a vacant state.

If a business is sold as a going concern, it's still priced as property (or lease) + inventory + the business itself.

If you want to tax a business based on its sales, income, inventory, or whatever, then pass legislation to impose that tax, don't try to call it part of the assessed value of the property.