Final answer:
The term 'fancy' in fancy ketchup is a USDA grade related to the tomato solid concentration, not necessarily its flavor or ingredient profile. Pricing and availability of ketchup types vary by brand and region, and there is no strict rule about their use in different dining establishments.
Step-by-step explanation:
The question relates to the differences between regular and fancy ketchup. Firstly, while both types of ketchup are variations of the same condiment, fancy ketchup typically refers to a product that meets certain U.S. Department of Agriculture (USDA) standards regarding viscosity and solid content, thus supposedly being of higher quality. The term 'fancy' is an actual USDA grade, determined by a specific Brix scale, which measures the concentration of tomato solids in the product. A fancy ketchup must have a higher tomato solid concentration than lower grades. This does not necessarily mean it has additional spices or flavors compared to regular ketchup.
Secondly, the perception that fancy ketchup has a sweeter and tangier flavor is subjective and not strictly defined by the USDA standards. Flavor might vary greatly between brands. Thirdly, the availability and pricing of ketchup can depend on brand, packaging, marketing, and regional availability rather than its USDA grade. Finally, the notion that fast food restaurants use regular ketchup and fine dining establishments prefer fancy ketchup does not reflect an industry standard and is more of a generalized stereotype.