That is a pretty thick floor and it all looks to be new... :shock: er... that is.
We did come across a 100 year old house that a lady was restoring in a historical district. When we checked out the registers, there was 4.25 inches of floor!!! 1x6 diagonal pine plank covered in 3/4 plywood, covered in 2 different layers of hardwood. And in this one particular area, two layers of vinyl and underlayment. For some reason the floor was sloped... Lady ended up having a structual engineer come out and declared all the layers had to come out or the supports would give out. She ended up gutting the place, having a large contruction and engineering firm perform the renovation to make the house "safe" again.
Some installers are just plain lazy or cheap. There are too many firms that will install a nice floor over an old one in the wrong conditions and compromise the new floor.