To add to this (as a Hong Kong native): Hong Kong is definitely a weird, special case, having belonged to Britain until 1997 and basically most people growing up there on some level despise the mainland, communism, and the language. To this day there's a certain level of disdain and judgment against you if you speak Mandarin there, almost like you're branded as "the others".

It's also true that provinces with rich cultures far away from Beijing continue to have their local dialects thrive. This is very true of Guangdong and Sichuan/Chongqing (see Sichuan rap). Yunnan also is quite noted for having many minorities and dialects still being preserved. The same cannot be said for Shanghai, where the younger generation have been eager to adopt to just speaking Mandarin as the mainstream thing to do. I had a girlfriend from Wuhan, and she grew up listening to the dialect there but her parents never encouraged her to converse in it, so she only speaks Mandarin.