Maybe nowadays the authentic restaurants might be more expensive, but I think historically it's been the other way round. The authentic restaurants were cheaper

Maybe nowadays the authentic restaurants might be more expensive, but I think historically it's been the other way round. The authentic restaurants were cheaper and opened to support the local immigrant population who wanted they tastes they were familiar with and missed from home, but the more expensive restaurants had the foods adapted to the local tastes so that they'd appeal to a wider range of people. If you look at Chinese restaurants in the UK, the older ones have radically different menus to the newer ones that cater primarily to Chinese students. The former is mostly based on Cantonese cuisine, but changed significantly to what Westerners expect, the latter is from all over China and usually pretty authentic.