Chinese dialects, esp. in the south, continue to thrive. I don't see a systematic move in China to kill them off. Maybe some people see the promotion of mandarin as an attempt to kill them off...or as an indirect means to downgrading their use.
This is quite different from Singapore which intentionally tells its citizens NOT to
speak dialects but only Mandarin.
北方方言(包括西南方言)的生存环境最好；其次是粤语的生存环境也很稳定； 但是在大力推广普通话后，没有很好保护吴语方言。比如在上海，除了允许沪剧越剧滑稽剧等戏曲存在外，报刊不准刊登上海方言文章，一个时期还停止上海话的广播，不准发行上海话歌曲磁带，不准讲上海话的电影电视片播出和方言话剧的演出，也不组织专家审定方言用字，因此上海方言还停留在不见书面语的状态。而上海话原来是一个十分丰富的方言，尤其是近代社会中，从自来水、电灯泡、马路、洋房，从出租车到沙发、麦克风、文化、经济、报馆等等，上海话中一时造出和引进大量词语，现在却到需要保护的时候了。 - 钱乃荣，上海大学中文教授。
"Northern Dialects (Mandarin dialects including Southwest Mandarin) have the best dialect development environment, followed by Cantonese which also has a relatively stable environment. However, the Wu dialects were not adequately protected from the intensive promotion of Mandarin. For example in Shanghai, other than for a few permited Hu 沪 and Yue 越 Operas live performances, Shanghainese articles are not permitted to be published in any newspaper; for a period even Shanghainese advertisements were barred; Shanghainese music tapes and CD's are banned; television stations are prohibited from using Shanghainese and even prohibited from broadcasting local Hu and Yue Opera programs; linguists were also barred from assigning Chinese characters for indigenous Shanghainese and Wu words, hence Shanghainese to this day remains in a non-literary state. But Shanghainese originally was an extremely expressive and well-endowed dialect, and now it is in need of our protection."
-Qian Nairong, Shanghai University, Professor of Chinese Language