While agree with the general sentiment, there are exceptions. The Shang dynasty had the longest reign in China (554 years). The Habsburg family ruled Austria for about 600 years. Paraphrasing [1]: The Japanese ruling 'family' recognises 125 monarchs beginning with the legendary Emperor Jimmu (traditionally dated to February 11, 660 BC) and continuing up to the current emperor, Akihito. Historical evidence for the first 29 emperors is marginal by modern standards, but there is firm evidence for the hereditary line since Emperor Kinmei ascended the throne 1500 years ago.

[1] https://en.wikipedia.org/wiki/Imperial_House_of_Japan