There is one enemy of all vintage vehicles, its name is rust. Vespas are fairly succeptable to rust, especially as their paint gets old and thin. Some rust can be repaired, or rusty parts replaced. One place you really can't do anything with is if the central tunnel gets eaten by the rust monster. Doctor, this one here, is terminal...
Yowza! That's rust! Yes, it appears that you can see the concrete between the gaps at the back of the floor runners. I'm not sure what is actually holding that whole area of the floorboards together...