My home had gas and electric. Though it was wired already it still had up grades over the years. Depending on how gentle someone wished to be accounts for the sloppy cuts. Also the room in photo 27 I would guess had carpeting even when this home was first built. Also we use boxes or pucks set in the ceiling now by code. Back when this house was built they could drill a small home in the plaster ceiling and just have bare wires hanging for the light. They used an hanger on some if not most early electrical lighting called a “Crows foot” which could mount right on the ceiling. The photo that you reposted shows a better job of running new wire. I use a sharp blade or Drummel tool to cut the sides of a board to disconnect the tongue and grove. I use finish trim pry bars to pull the board out. If my measurements are right I only have to remove a few boards to get new wiring ran. Done this more then I care to think about. Key is I care, the person who cut open the floor in photo 27 probably didn’t care much. Even in attic spaces I am as careful. I just don’t believe in sloppy work, which photo 27 in my opinion is. Still in the end this is not for venting or any other use but to either run new wiring or to fix something. In my last house I think an issue happened with the gas pipe in the ceiling. This ancient repair would also lead to what we are seeing.