I think the English-speaking peoples should adopt this rule.

They did, going through a period of capitalizing most nouns during the 18th century, but it's died off. The Germans also experimented with not capitalizing nouns during the second half of the 19th century, but it didn't catch on either. (I have some books using this strange orthography and they look very weird.) The Ancient Egyptians used to put a cartouche around proper names and other ancient Near Eastern languages (e.g., Akkadian or Sumerian) used particles called determinatives to indicate that a word in cuneiform was a person's or a place's name. These still get transliterated, but were probably not pronounced.