The opposite of "most upscale" would be "least upscale" or simply "downscale". These terms describe something that is less luxurious or considered less high-end. For example, a "least upscale" restaurant might be a fast-food chain or a budget-friendly diner, while a "downscale" clothing store may offer more affordable, budget-friendly clothing options. These terms are often used to describe goods or services that have a lower price point or are aimed at a different demographic than high-end or luxury products. While "most upscale" implies a level of success and exclusivity, "least upscale" or "downscale" has its own appeal and caters to a different market.