The five-fold correspondence between English and Chinese peerage ranks is merely coincidental. There is nothing special about the number five. The history of European noble ranks, both linguistic and chronological, is informative.
In England, all nobles are by definition Barons - that being the minimum dignity granted following the 1066 conquest granted to all tenants-in-chief of the English crown. In addition a few dozen of these Barons were granted the additional dignity of Earl. Only over time were the additional peerage dignities of Duke (both Royal, non-hereditary and restricted to the Royal family, and Noble), Marquess (Baron of a March), and Viscount, the full suite taking about 400 years to develop. The usage of Lord enters the language also at this time as the semiformal address shared by all Barons.
In Germany (or, if you prefer, the German-dialect-speaking lands of the Holy Roman Empire) the original titles are Graf (or Count, - equivalent to English Earl), Herzog (equivalent to English Duke) and Furst (equivalent to English Prince but a hereditary and not courtesy title). The very many additional German peerage titles largely spring from these, as witness Kurfurst for Prince Elector, Großherzog for Grand Duke, and finally all of Markgraf, Landgraf, Reichsgraf, Burggraf*, and Altgraf* in some sort of correspondence to English Marquess, Earl and Viscount. In German the form of address Graf (technically translated as Count, but in this usage better translated as Lord) is adopted as the semiformal address for many of these peerage ranks.
France, Spain, Poland and other Western European countries all have additional historical quirks in their peerage developments.
Note that in both England and the H.R.E. the peerage levels "built up" from the base of either Baron or Graf, so that the base semi-formal address remains the lower one. It appears that in China the additional peerage ranks "built down" instead, so that the base semi-formal address retained was the original, higher in this instance, one.