Zhongguo wasn't used in its modern sense in 1849 and 1949. That's the point. It wasn't until the early 20th century, when Zhongguo became a term used to describe the Chinese nation-state in the Western sense. This was also when the term Jhonghua Minguo was coined. Thank you for revealing that you have no grasp of the historic development of the Chinese language.
China is called Zhongguo in Mandarin Chinese. The first character zh¨ng (ÖÐ ) means "middle" or "central," while gu¨® (¹ú or ‡ø ) means "country" or "state". The term can be literally translated as "Middle Kingdom" or "Central Kingdom." In ancient times the term referred to the "Central States" along the Yellow River valley. English and many other languages use various forms of the name "China" and the prefix "Sino-" or "Sin-". These forms are thought to be probably derived from the name of the Qin Dynasty that first unified the country (221-206 BCE).[1] The Qin Dynasty unified the written language in China and gave the supreme ruler of China the title of "Emperor" instead of "King," thus the subsequent Silk Road traders might have identified themselves by that name.
At least Wikipedia thinks you are full of crap too.
I will find other sources as well.