In the 21st century in many countries, it is difficult to function without a birth certificate. Settling up an estate may be difficult without a death certificate. This was not necessarily the case in 1912 or 1812. Your ancestor very easily might not have a record of his birth or death, particularly for events that took place two hundred years ago.
It would have been a little more difficult for your 1812 ancestor to function without deeds to his property, paying his taxes, or settling up his father's estate. That's why those records are more likely to exist. Records of property are often one of the earliest records--much earlier than who was born or who died.