I didn't interpret their comment as suggesting that modern consumers would be familiar with a floppy disk, but instead was pointing out that regular consumers in the past often handled floppy disks, which made a good case for it being a common symbol at that time. However, since SSD's aren't used so commonly by average consumers, it may not make a good replacement as a symbol.

That would suggest that perhaps there is a more commonly recognized object that can be represented skeuomorphically. Off the top of my head, an SD card may be a good option.